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A008327 Triangle read by rows: T(n,k) is the number of simple regular bipartite graphs with 2n nodes and degree k, (0 <= k <= n). 2
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 4, 6, 4, 1, 1, 1, 1, 4, 14, 14, 4, 1, 1, 1, 1, 7, 41, 130, 41, 7, 1, 1, 1, 1, 8, 157, 1981, 1981, 157, 8, 1, 1, 1, 1, 12, 725, 62616, 304496, 62616, 725, 12, 1, 1, 1, 1, 14, 4196, 2806508, 78322916 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,13

LINKS

Table of n, a(n) for n=0..71.

B. D. McKay and E. Rogoyski, Latin squares of order ten, Electron. J. Combinatorics, 2 (1995) #N3.

EXAMPLE

Triangle begins:

  1,

  1, 1,

  1, 1, 1,

  1, 1, 1,   1,

  1, 1, 2,   1,    1,

  1, 1, 2,   2,    1,    1,

  1, 1, 4,   6,    4,    1,   1;

  1, 1, 4,  14,   14,    4,   1, 1;

  1, 1, 7,  41,  130,   41,   7, 1, 1;

  1, 1, 8, 157, 1981, 1981, 157, 8, 1, 1;

  ...

CROSSREFS

Column k=2..3 are A002865, A008325.

Row sums are A008324.

Cf. A008326, A087114.

Sequence in context: A047996 A227690 A063686 * A133687 A215870 A097587

Adjacent sequences:  A008324 A008325 A008326 * A008328 A008329 A008330

KEYWORD

nonn,tabl,nice

AUTHOR

Brendan McKay

EXTENSIONS

More terms from Eric Rogoyski, May 15 1997

Name clarified by Andrew Howroyd, Sep 05 2018

STATUS

approved

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Last modified December 11 13:08 EST 2018. Contains 318049 sequences. (Running on oeis4.)