٥륯åĥ
ͤλ礹ȤơüԿ3+1
4ͤĤǹԤΤǡϣΡ߻üԿ4
üԿȻϤɤ餫ʤ⤦ϴʤΤǡüԿޤϣΤ4ܿˤʤȤͤȡΡ1458912Ȥʤꡢ312+137ȤʤޤǽϣΤ4ܿξȤƤޤ
ºݤȤ߹碌Ū˲ǽɤޤǤϤޤڤƤʤȤŬʲǤ
1020ڡ 0:20:26 45386
ʪ
ɽͤƤΥޥοͤn(n-1)ޥˤʤ뢨ʬvsʬ
1жɤ12ޥޤ뤳Ȥȯ¨n(n-1)12ܿ
1ƱǤΤ3ͤʤΤ(n-1)3ܿ
ʾϤʤΤǤ­nơn=376ܤ˾
[ޤβˡƤʤΤdzξڤƤޤ^^;]

ߤ3Ǥ(3ͤǶ)ʤΤäơ41ȤǹԤ򺮺ߤʤ顢ɤʤǤ礦
1020ڡ 0:24:02 HomePage:Twitter45387

ƱʬǤ뤳ȤȽǤƤޤ
1020ڡ 0:24:11 45388

񤷤äǤorz
ޤͤۤƤλüԤǤ뤳ȤοͿ3n+1Ǥפȡ롼׿n(n-1)/12Ȥʤ뤳Ȥn(n-1)/12ǤפȤ2Ĥɬ׾Τ6ܤ˾ޤ
ľʬ򸡾ڤƤ餺äƤޤä褦ʷʤΤǡijͤβˡ򻲹ͤˤǤ
1020ڡ 0:25:50 45389
ʪ
̤ǾͤƤߤޤ^^;
1020ڡ 0:29:12 HomePage:Twitter45390
̤ꤹ1
ޡΥ롼褯狼ޤ
񤷤äǤ͡
񡡡 1020ڡ 0:30:46 HomePage:ͤοʳƮ45391
٥륯åĥ
ͤλ4üԿ13ͤξȤ߹碌äƤߤ褦Ȥޤͽ̤꺤ǡ6ܤޤǤ٤ƲǽǤ뤳Ȥ򼨤ΤϸŪǤϤʤǤۤοͤβˡ˴ԡ
1020ڡ 0:32:04 45392
̤ꤹ1

ͤͤƤߤޤ
񡡡 1020ڡ 0:33:23 HomePage:ͤοʳƮ45393
̤ꤹ1
üԿͿ13ͤλ
줾X,X1.......X13Ȥޤ
(ޤX1˹ͤ)X1X2X4X5X7X8X10X11X13Ǥ礦Ȥˤʤޤ
ƱȤX2.......X13Ǥ⤹(Ǥ)(ϼʤΤǼºݤ˽񤭤ޤ)
Ǥ礨ޤ
񡡡 1020ڡ 0:49:04 HomePage:ͤοʳƮ45394
߼Ψ繥ʹ
1ǯǤ7ǯ֤Ƥߤޤޤ³ƤȤˤӤäꤷޤ
񤷤Ǥ͡ʬƤʤΤDz򤱤ޤ
1020ڡ 1:15:04 45395
߼Ψ繥ʹ
1ǯǤ7ǯ֤Ƥߤޤޤ³ƤȤˤӤäꤷޤ
񤷤Ǥ͡ʬƤʤΤDz򤱤ޤ
1020ڡ 1:16:35 45396
ǯ
#45387#45389ƱǤ
n*(n-1)/2nͤοˤ64ͤοˤܿǡn-131ˤܿn-13ܿǤ뤳Ȥ˵դΤ˻֤äơ
4, 13, 16, 25, 28, 37, 40, ....
ȤꤢȤȤǡο줿
1뤤412IJäƤäǤ͡2ˤʤȤΤȽξȤΩΤʥ

1020ڡ 14:17:44 45397
ϥ饮㡼ƥ
ȻפäƤޤ
1020ڡ 5:53:09 HomePage:湩ؤ˥45398

1620νʬϰʲΤȤꡧ
(1,2,3,4)
(1,5,6,7)
(1,8,9,10)
(1,11,12,13)
(1,14,15,16)
(2,5,9,13)
(2,6,12,16)
(2,7,10,15)
(2,8,11,14)
(3,5,8,16)
(3,6,10,11)
(3,7,13,14)
(3,9,12,15)
(4,5,11,15)
(4,6,9,14)
(4,7,8,12)
(4,10,13,16)
(5,10,12,14)
(6,8,13,15)
(7,9,11,16)

2550礭ˤĤư̲Ǥ褦ˡϤ狼ޤ
1020ڡ 14:27:31 45399
uchinyan
Ϥˤϡơϡ
ࡤŪ˻ΥѥĴٵ§򸫤Ĥ褦ȤΤǤ
ޤϤޤäƤޤޤ
ʤΤǡɬ׾Ĵ١줬ǽץȤߤޤ

ޤɬ׾ؤݤǤʤ
ͤ n 礹ȤȡꡤüԿ 3n+1 ͡ΤϤǤ
ǡϣͤǹԤΤǡϡn(3n+1)/4 硤ΤϤǤ
줬ˤʤϤʤΤǡn ϡ4 ܿ 4 dzä 1 ;Ǥ
Ĥޤꡤn = 1, 4, 5, 8, 9, 12, ...ʤΤǡ
üԿ3n+1 = 4, 13, 16, 25, 28, 37, ...ꡤܤ 37 ͤˤʤޤ
ɤ顤 37 ͤȤʤäƤ褦Ǥ

ȤϤθ塣ºݤ˼¸Ǥ뤫Ǥ
褯ʬʤäΤǡn ͤξ硤üԤ 1 n ֹդ
ʥ١åǼΤ褦ʥץȤߤޤ

LET m = 40
DIM p(m,m), s(10000,4)

FOR n = 4 TO m
MAT p = ZER
LET cnt = 0
FOR a = 1 TO n-3
FOR b = a+1 TO n-2
LET f = 0
FOR c = b+1 TO n-1
FOR d = c+1 TO n
IF (p(a,b) + 1 <= 1) AND (p(a,c) + 1 <= 1) AND (p(a,d) + 1 <= 1) AND (p(b,c) + 1 <= 1) AND (p(b,d) + 1 <= 1) AND (p(c,d) + 1 <= 1) THEN
LET p(a,b) = p(a,b) + 1
LET p(a,c) = p(a,c) + 1
LET p(a,d) = p(a,d) + 1
LET p(b,c) = p(b,c) + 1
LET p(b,d) = p(b,d) + 1
LET p(c,d) = p(c,d) + 1
LET f = 1
LET cnt = cnt + 1
LET s(cnt,1) = a
LET s(cnt,2) = b
LET s(cnt,3) = c
LET s(cnt,4) = d
EXIT FOR
END IF
NEXT d
IF f = 1 THEN
EXIT FOR
END IF
NEXT c
NEXT b
NEXT a
LET f = 0
FOR i = 1 TO n-1
FOR j = i+1 TO n
IF p(i,j) < 1 THEN
LET f = 1
END IF
NEXT j
IF f = 1 THEN
EXIT FOR
END IF
NEXT i
IF f = 0 THEN
PRINT n
FOR i = 1 TO cnt
PRINT i; ":"; s(i,1); s(i,2); s(i,3); s(i,4)
NEXT i
REM FOR i = 1 TO n
REM FOR j = 1 TO n
REM PRINT p(i,j);
REM NEXT j
REM PRINT
REM NEXT i
END IF
NEXT n

END

̤ϡ

4
1 : 1 2 3 4
13
1 : 1 2 3 4
2 : 1 5 6 7
3 : 1 8 9 10
4 : 1 11 12 13
5 : 2 5 8 11
6 : 2 6 9 12
7 : 2 7 10 13
8 : 3 5 9 13
9 : 3 6 10 11
10 : 3 7 8 12
11 : 4 5 10 12
12 : 4 6 8 13
13 : 4 7 9 11

üԿ4 ͤ 13 ͡ξʤ줿ΤǤ
16 37 ͤξϲޤ

ץबְäƤΤǤ礦
ʬ餺ǺǤޤ

ʤ嵭ץˤϸꡤȤå­ޤ
٤ƤβǽʣͤΥѥåϤƤΤǤ
åν֤ñ㤹ưټԤȤƤޤȤߥȤޤ
ºݤˤϡ٤μԤǤ᤺˥ХåȥåƺĩΥåɬפǤ͡
Ѥ򤫤ƤޤޤʬؤβΤˡƻĤƤޤ
1020ڡ 15:41:34 45400
uchinyan
졤16 ͤξζ㤬Фޤ͡
ϤץबְäƤ褦Ǥʤ
1020ڡ 15:00:43 45401
uchinyan
ǼĤɤߤޤ


ʲεҤϡ⤽ϻ伫ȤٶΥ˲᤮ʤΤǤ
޳ѤʤΤǤͤޤǤˤȻפäƸΤǤ
Ȥ⤢äơˡʬϻ F.A.Q. ΡֻϰϡפεҤ򻲹ͤˡ
ĿͤǤиǼŪ˹ԤäƤΤǤäơҴŪʤΤǤϤޤ
ޤǤ⤴ͤǤ餺

ϡɬ׾ͤޤǡȤˡ¿褦Ǥ
ºݤ˲ǽνʬϡԺϥץࡤȤȤˤʤꤽǤ

ɬ׾Ĵ٤ˡʬࡣ

#45386#45400
ͤλ n ȤȡüԿ 3n+1 ͡ϡn(3n+1)/4 硤ˡ

#45387#45389#45397
n ͤξ硤 n(n-1)/12 硤磴ͤ n-1 3 ܿꡤˡ
1020ڡ 16:21:06 45402
ˤ
Ȥꤢ
n򣳸ĤĤդ䤷ơ
n(n-1)12dzΤɬ׾ʤΤ
37Ǥޤ
ʬǤ뤫ϡޤͤƤޤOrg
1020ڡ 17:19:57 MAIL:nikotan@fat.coara.or.jp 45403
̤ꤹ1
ޤĩԤο۾露ʤǤ
Ǥ͡
񡡡 1020ڡ 18:30:58 HomePage:ͤοʳƮ45404
ޥ
ĤϡʬˤĤƤθڤ򤻤˽ꤷƤޤäƤޤޤ...աǼĤǸƤϤơ֤áפȻפäǡڤߤΤǤʤʤ...m(__)m
MacBook Pro 1020ڡ 19:38:23 HomePage:45405
̤ꤹ1

ɽ񤤤ƤС
ʤƹͤϼˤޤ
񡡡 1020ڡ 23:39:24 HomePage:ͤοʳƮ45406
baLLjugglermoka
Ϥ꽽ʬˤĤƤϳͼƤޤͤ͡ϡ13®ǸĤƤϡͤơ̲ΤΡǥˤʤ..,
1020ڡ 23:42:53 45407
⡼ޥ
褯狼ޤǤ ^^;
ǿѷǹͤꤷƤޤĶǤޤ^^;;
#45400 uchinyanΤ狼䤹Ǥ

缭ŵǡ
A228137 Numbers that are congruent to {1, 4} mod 12.
ˡa(n) = a(n-1) +a(n-2) -a(n-3)
ȤܤäƤޤ
ΰ̣β狼餺
1020ڡ 23:59:07 45408

2550νʬϰʲΤȤꡧ

(1,2,3,4)
(1,5,6,7)
(1,8,9,10)
(1,11,12,13)
(1,14,15,16)
(1,17,18,19)
(1,20,21,22)
(1,23,24,25)
(2,5,8,11)
(2,6,14,18)
(2,7,20,25)
(2,9,19,23)
(2,10,15,22)
(2,12,16,24)
(2,13,17,21)
(3,5,21,23)
(3,6,9,12)
(3,7,15,19)
(3,8,16,20)
(3,10,17,24)
(3,11,18,22)
(3,13,14,25)
(4,5,16,17)
(4,6,22,24)
(4,7,10,13)
(4,8,18,25)
(4,9,14,21)
(4,11,15,23)
(4,12,19,20)
(5,9,15,25)
(5,10,18,20)
(5,12,14,22)
(5,13,19,24)
(6,8,19,21)
(6,10,16,23)
(6,11,17,25)
(6,13,15,20)
(7,8,14,24)
(7,9,17,22)
(7,11,16,21)
(7,12,18,23)
(8,12,15,17)
(8,13,22,23)
(9,11,20,24)
(9,13,16,18)
(10,11,14,19)
(10,12,21,25)
(14,17,20,23)
(15,18,21,24)
(16,19,22,25)

ޤ 1֤ (2,3,4),(5,6,7),ġ,(23,24,25) 8ȤȤޤ
ƻĤ42ȤˤĤƤϡ1֤24ͤ
A:(2,3,4) (5,6,7)
B:(8,9,10) (11,12,13)
C:(14,15,16) (17,18,19)
D:(20,21,22) (23,24,25)
4롼פʬơ4Ȥ AD롼פΤ줾ʬѥ
2͡2͡18
1͡1+1+1͡24
ȤʤȤޤǹʤǡȤϴǥѥޤ

2863ǤŪˡϤޤ褯狼ޤ
1021ʶ 18:44:27 45409
ˤ⡼
ФĻϿ̤ꡢޤۤǤ
ϡƤäݤǣ߾ǹͤ顢
4096ȤäФƤޤ路ޤ
ͿȻǼΩƤƹͤޤäȿؤää

֤οͿ餺ǤפȤʬ
ڤʤäΤǤʲΤ褦˹ͤޤ

ޤͤ˾ƤȡAȤ
οȤơA魯Ϳϣ͡
äơͿϡܣ͡

οͿ줾Τ顢
߿Ϳϡʣܣˣ

礢ꣴͤǤ뤫顢
Ϳϭʣܣˣ줬ˤʤõ

ʣܣˣdzФ褤
ξϣᣰmodˡܣᣰ

ᣰmodˤϡۤ顢
飶ܤᣱȤʤ뤫顢ͿϭˤƤϤᡢ

ʾ
޻Ա¶ʼΡˡ 1021ʶ 20:00:34 45410
kyorofumi
case of 28 people:

1 2 3 4
1 5 6 7
1 8 9 10
1 11 12 13
1 14 15 16
1 17 18 19
1 20 21 22
1 23 24 25
1 26 27 28
2 5 6 7
2 8 9 10
2 11 12 13
2 14 15 16
2 17 18 19
2 20 21 22
2 23 24 25
2 26 27 28
3 5 6 7
3 8 9 10
3 11 12 13
3 14 15 16
3 17 18 19
3 20 21 22
3 23 24 25
3 26 27 28
4 5 6 7
4 8 9 10
4 11 12 13
4 14 15 16
4 17 18 19
4 20 21 22
4 23 24 25
4 26 27 28
5 8 9 10
5 11 12 13
5 14 15 16
5 17 18 19
5 20 21 22
5 23 24 25
5 26 27 28
6 8 9 10
6 11 12 13
6 14 15 16
6 17 18 19
6 20 21 22
6 23 24 25
6 26 27 28
7 8 9 10
7 11 12 13
7 14 15 16
7 17 18 19
7 20 21 22
7 23 24 25
7 26 27 28
8 11 12 13
8 14 15 16
8 17 18 19
8 20 21 22
8 23 24 25
8 26 27 28
9 11 12 13
9 14 15 16
9 17 18 19
9 20 21 22
9 23 24 25
9 26 27 28
10 11 12 13
10 14 15 16
10 17 18 19
10 20 21 22
10 23 24 25
10 26 27 28
11 14 15 16
11 17 18 19
11 20 21 22
11 23 24 25
11 26 27 28
12 14 15 16
12 17 18 19
12 20 21 22
12 23 24 25
12 26 27 28
13 14 15 16
13 17 18 19
13 20 21 22
13 23 24 25
13 26 27 28
14 17 18 19
14 20 21 22
14 23 24 25
14 26 27 28
15 17 18 19
15 20 21 22
15 23 24 25
15 26 27 28
16 17 18 19
16 20 21 22
16 23 24 25
16 26 27 28
17 20 21 22
17 23 24 25
17 26 27 28
18 20 21 22
18 23 24 25
18 26 27 28
19 20 21 22
19 23 24 25
19 26 27 28
20 23 24 25
20 26 27 28
21 23 24 25
21 26 27 28
22 23 24 25
22 26 27 28
23 26 27 28
24 26 27 28
25 26 27 28
1021ʶ 20:06:54 45411
kyorofumi
the solution was wrong... sorry
1021ʶ 20:27:16 45412
Halt0
37 Ǵְ㤤ʤ褦Ǥ. ȤΤ, Ĵ٤Ȥ, üԿ mod 12 1 ޤ 4 Ȥ, ξ褦ʻȤ߹碌¸ߤ뤿ɬ׽ʬǤ, Ⱦ餷ʸ򸫤ĤǤ. äȤ, ɤΤϻμ;Τ, ̣ΤɤǤߤƤ.

ޤ,

https://en.wikipedia.org/wiki/Steiner_system
"A Steiner system with parameters t, k, n, written S(t,k,n), is an n-element set S together with a set of k-element subsets of S (called blocks) with the property that each t-element subset of S is contained in exactly one block. In an alternate notation for block designs, an S(t,k,n) would be a t-(n,k,1) design."

Ϥ t=2, k=4 ξˤޤ. Ĥޤ, Steiner system S(2,4,n), 뤤 block design θդǤ 2-(n,4,1) design ¸ߤ褦 n ξ뤳Ȥˤʤޤ.
, ˤĤƽ񤫤ƤΤʸǤ.

https://projecteuclid.org/euclid.aoms/1177705047

ˡ㤤ޤ, ʸ balanced incomplete block design (BIBD) B[k,,v] ȤΤ, θդǤ block design 2-(v,k,) ΤȤǤ. 줬ΤꤿΤ k=4, =1 ξ, ʤ BIBD B[4,1,v] ¸ߤ뤫ɤǤ, 6 ϤΤϤȤ
"A necessary and sufficient condition for the existence of BIBD of v elements, with k=4 and any is that
(v-1)0 (mod 3) and v(v-1)0 (mod 12)"
Ȥޤ. v (ΡֻüԿפˤ) v1,4 (mod 12) Ȥ BIBD B[2,1,v] ¸ߤ뤳Ȥɬ׽ʬǤ뤳Ȥ狼ޤ.
1022ڡ 4:33:07 45413

#45413
ʸĤƤäƤ꤬Ȥޤȹ礻ǥǤ͡ʲǯˤʬȤιֱʹȤΤǤäѤ狼ʤäΤФƤޤˡ
1022ڡ 11:28:58 45414
uchinyan
#45413
Halt0󡤾򤢤꤬Ȥޤ

ʤۤɡʸΤǤʤʤΤ褦Ǥ͡
֤򸫤ĤƾƤߤ⤷ޤ
ʬǿͤǤǶؤζܥ٥οؤʤäƤꡤ
ʬꤽˤʤ (^^;

Ǥ⡤괺פʬäƤ褫äǤ
1022ڡ 15:11:18 45415
Halt0
ˤ.
⤦ˤʤΤǤˤʤäƤ⾯ʤ⤷ޤ,
ɵˤʤäΤ, ̤λ򻲹ͤˤ, Ϳ n n=25,28,37 ξβƤߤޤ.

D. Stinson. Combinatorial Designs: Constructions and Analysis
http://mathscinet.ru/files/StinsonD.pdf

򻲾Ȥޤ.
ľܺȤ꤬Τ p.167~ Ǥ.
嵭 pdf ɤǤۤᤤ⤷ޤ, äʤΤǤ˹Ӥξ񤤤Ƥߤޤ.
νŪμ򤹤뤳ȤǽǤ.

(#45413 ˽񤤤Ȥ, Ϳ n n1,4 (mod 12) Ȥɬ׽ʬ餷,
嵭 pdf ⤳ΤȤƤߤʤΤǤ, ϤޤǤϥեǤƤޤ.
Ǥ, 嵭ǤϤΤȤ뤿ΥƥåפȤ, n=13,16,25,28,37 Ǹ̤˶Ƥޤ.
, ΤŪʥ르ꥺǤϼ갷ʤȤȤʤΤǤ礦.
ʤΤ, n=25,28,37 ιΤɤǤߤޤ.
(n=25 βϴ˷ǼĤ󼨤Ƥޤ, n=37 ȹλƱͤʤΤ, ɤߤޤ)
ʤ, ФɤߤʤΤ, ˤϻμ꤬äƤ, äƸλˤϤʤ꤬ǽޤ.)

----------------------------------------
[ˡ]
S θο |S| Ƚ.
Z n ˡȤ;ෲ Z/nZ Ƚ.
G_1 G_2 ľѤ G_1 G_2 Ƚ.

[]
ͭ½ (X,) 2-(n,4,1) design ǤȤ,
Ծ0 |X|=n
Ծ1 B Ф BX, |B|=4
Ծ2 Ǥդ x,yX, xy Ф, {x,y}B ʤ B 1 ¸ߤ
Ȥ򤤤.

2-(n,4,1) design n=25,28,37 ΤȤ˹褦.
(X üԤν, n οͿ, B Ԥ줿Ȥˤ.)

n=25 ΤȤ
G = (Z/5Z) (Z/5Z) Ȥ,
a[1,1]=(0,0), a[1,2]=(0,1), a[1,3]=(1,0), a[1,4]=(2,2)
a[2,1]=(0,0), a[2,2]=(0,2), a[2,3]=(2,0), a[1,4]=(4,4)
G θȤ.

[1]
Ǥդ gG, g0 Ф
1 Ĥ i{1,2} j,k{1,2,3,4}, jk ä
g=a[i,j]-a[i,k] Ǥ.
[]
243=24 ̤ i,j,k ȤˤĤƼºݤ˷׻ƳΤʤΤά.

i=1,2, gG Ф,
B[i,g] = {a[i,1]+g, a[i,2]+g, a[i,3]+g, a[i,4]+g}
.
X = G,
= {B[i,g] |i{1,2}, gG}
Ȥ.

ΤȤԾ0աԾ1դ餫.
Ծ2դ򼨤. x,yX, xy Ȥ.
1, 1 Ĥ i,j,k (jk) ä
x-y=a[i,j]-a[i,k] Ǥ.
g=x-a[i,j] Ȥ, x=a[i,j]+g, y=a[i,k]+g {x,y}[i,g] Ǥ,
ޤλ, Τ褦 [i,g] Ϥ 1 Ĥ˷ޤ.
ä (X,) 2-(25,4,1) design Ǥ.

n=37 ΤȤ
G=Z/37Z Ȥ,
a[1,1]=0, a[1,2]=1, a[1,3]=3, a[1,4]=24
a[2,1]=0, a[2,2]=10, a[2,3]=18, a[2,4]=30
a[3,1]=0, a[3,2]=4, a[3,3]=26, a[3,4]=32
G θȤ.
n=25 ΤȤƱͤ (i{1,2,3} Ѥ) Ω, Ʊͤ˹Ǥ.

n=28 ΤȤ
n=25,37 ȤϾä򤹤.
G = (Z/3Z) (Z/3Z) (Z/3Z) Ȥ,
a[1,1]=(0,0,0), a[1,2]=(0,2,0), a[1,3]=(1,1,1), a[1,4]=(2,1,1)
a[2,1]=(0,0,0), a[2,2]=(1,0,2), a[2,3]=(0,1,2), a[1,4]=(1,1,0)
G θȤ.

[2]
Ǥդ gG, g0 Ф
g=a[i,j]-a[i,k] Ȥʤ褦 i,j,k (jk) Ϲ⡹ 1 Ĥʤ. ( 1 Ĥʤ⤢)
[]
׻ʤΤά.

G ˴ޤޤʤ ͤ, X = G {} Ȥ.
i=1,2, gG Ф,
B[i,g] = {a[i,1]+g, a[i,2]+g, a[i,3]+g, a[i,4]+g}
, ޤ, a,bZ/3Z Ф
B'[a,b] = {(a,b,0),(a,b,1),(a,b,2),}
Ȥ.

ΤȤ, B[i,g] ηθ (227=54 ) B'[a,b] ηθ (9 ), 63 Ĥθʤ ͤ, (X,) Ͼ.
Ծ0աԾ1դ餫ʤΤǡԾ2դ򼨤.

[3]
B_1,B_2 (B_1B_2) Ф, ζʬ 2 İʾθޤޤʤ.
[]
B_1, B_2 Τ B'[a,b] η򤷤Ƥʤ, 2 (n=27 ΤȤΡԾ2դξƱ褦ˤ) .
ޤ, B'[a,b] η򤷤Ƥ, ʬ餫 Τߤޤ.
ä B'[a,b] B[i,g] ζʬθ 1 İʲǤ뤳Ȥ򼨤о뤬,
i,g ꤷȤ B[i,g] 2 Ĥΰۤʤ븵 (a_1,b_1,c_1), (a_2,b_2,c_2) Ȥ
(a_1,b_1)(a_2,b_2) Ȥʤ뤳Ȥ餫Ǥ.

3, Ծ2 夯,
Ǥդ x,yX, xy Ф, {x,y}B ʤ B , ¸ߤȤФ 1 ĤǤ
. ,
|X|=28 , x,yX, xy Ȥʤ褦 x,y Ȥ߹碌, 2827/2=378 ̤ꤢ뤳Ȥ,
||=63 , B {x,y}B (xy) ΤȤ꤫ ||4C2=378 ̤ꤢ뤳Ȥ,
1 1 бˤԾ2դΤΤ.
ä (X,) 2-(28,4,1) design Ǥ.
----------------------------------------

Ĺʸ餷ޤ.

1023 2:35:00 45417
̤ꤹ1
#45417
ʤۤɡ
񡡡 1023 9:51:25 HomePage:ͤοʳƮ45418
ģ
̵ƤޤϫޤǤǤ͡˥󤵤Ʊͤ˸ڤϽ褺ʤΤĤޤ
1025ʲС 22:55:31 45419
X
βˡǤ߾nĤȤäơ줾Ǥ֤ʤͳѷǤΤ顢nϣܿĤǤĤͳѷο(n-1)/3 n򤫤Ƥ줾λͳѷ֤뤫顢n(n-1)/12 ǤʤȤʤ嵭Ĥ

˺ܤΤϤȤƤפ֤ꡢ٥եǻäƤޤ̣ꤢȲ򤳤Ȥޤϣʲδ򤫤碌Ʋꡣޤ
1026ʿ 8:27:33 45420
鯤ο
k(3k+1)/4ˤʤɬ׾ƣܤ˾ޤ
ʬγǧϡ4͡13͡16ͤޤǤޤ
Ż˿˻ơ꤮ˤʤޤ
1026ʿ 22:46:45 45421
鯤ο
3k+1ΣܤΤȡ
Ĺ֡13μְ㤨Ƥơ16ȤƤޤ
1026ʿ 22:48:47 45422
̤ꤹ1
ޤʡ
񡡡 1027ڡ 0:03:17 HomePage:ͤοʳƮ45423
baLLjugglermoka
졢ޤ͡
1027ڡ 0:04:11 45424
٥륯åĥ
Ϥ٤ߤǤ礦Ф餯ޤƤߤޤ
1027ڡ 0:05:39 45425
̾
ޥ뤵⤪˻ä̵򤻤
1027ڡ 0:09:14 45426