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A243510 Number of ways the maximal number of domicules can be placed on an n X n square. 3
1, 1, 3, 58, 280, 170985, 3037561, 35203565096, 3263262629905, 580992839261272720, 326207195516663381931, 811740344447523575023878026, 3011882198082438957330143630563, 98662906581850761030365769529236858241, 2565014347691062208319404612723752103028288 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Number of maximum matchings in the n X n king graph. - Eric W. Weisstein, Jun 20 2017

LINKS

Table of n, a(n) for n=0..14.

Eric Weisstein's World of Mathematics, Independent Edge Set

Eric Weisstein's World of Mathematics, King Graph

Eric Weisstein's World of Mathematics, Matching

Eric Weisstein's World of Mathematics, Maximum Independent Edge Set

Wikipedia, King's graph

FORMULA

a(n) = A243424(n,floor(n^2/2)).

EXAMPLE

a(2) = 3:

  +---+  +---+  +---+

  |o-o|  |o o|  |o o|

  |   |  || ||  | X |

  |o-o|  |o o|  |o o|

  +---+  +---+  +---+.

a(3) = 58:

  +-----+  +-----+  +-----+

  |o-o o|  |o o o|  |o o-o|

  |    ||  | X  ||  | \   |

  |o   o|  |o o o|  |o o o|

  ||    |  |     |  ||  / |

  |o o-o|  |o-o  |  |o o  |

  +-----+  +-----+  +-----+  ... .

CROSSREFS

Cf. A243511.

Even bisection gives A239273.

Sequence in context: A041735 A156487 A254653 * A024218 A049661 A295409

Adjacent sequences:  A243507 A243508 A243509 * A243511 A243512 A243513

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jun 05 2014

STATUS

approved

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Last modified June 22 17:18 EDT 2021. Contains 345388 sequences. (Running on oeis4.)