id:A035482 - OEIS Search Results

Search: id:A035482

Displaying 1-1 of 1 results found.

page 1

Number of n X n symmetric matrices each of whose rows is a permutation of 1..n.

+0
2

1, 1, 2, 6, 96, 720, 328320, 31449600, 440952422400, 444733651353600 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`The even and odd subsequences are A036980, A036981.`
	EXAMPLE	`a(3) = 6 because the first row is arbitrary (say, 213) and the rest is then determined. By symmetry the second row has to be 132 or 123 but in order for the third row/column to work it has to be 132.`
	CROSSREFS	`Cf. A000438, A035481, A000315, A002860, A003090, A040082.` `Sequence in context: A007188 A129364 A092287 this_sequence A007870 A081992 A066091` `Adjacent sequences: A035479 A035480 A035481 this_sequence A035483 A035484 A035485`
	KEYWORD	`more,nonn`
	AUTHOR	`Joshua Zucker and Joe Keane (joshua.zucker(AT)stanfordalumni.org)`

page 1

Search completed in 0.002 seconds

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.