A008764 - OEIS

This site is supported by donations to The OEIS Foundation.

A008764

Number of 3 X 3 symmetric stochastic matrices under row and column permutations.

1, 1, 2, 4, 6, 8, 12, 16, 21, 27, 34, 42, 52, 62, 74, 88, 103, 119, 138, 158, 180, 204, 230, 258, 289, 321, 356, 394, 434, 476, 522, 570, 621, 675, 732, 792, 856, 922, 992, 1066, 1143, 1223, 1308, 1396, 1488, 1584, 1684, 1788, 1897, 2009, 2126, 2248, 2374, 2504 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	FORMULA	`Expansion of (1+x^3)/(1-x)/(1-x^2)/(1-x^3)/(1-x^4).`
	EXAMPLE	`There are 6 nonisomorphic symmetric 3 X 3 matrices with row and column sums equal 4:` `[0 0 4] [0 1 3] [0 1 3] [0 2 2] [0 2 2] [1 1 2]` `[0 4 0] [1 2 1] [1 3 0] [2 0 2] [2 1 1] [1 2 1]` `[4 0 0] [3 1 0] [3 0 1] [2 2 0] [2 1 1] [2 1 1]`
	CROSSREFS	`Cf. A019298.` `Sequence in context: A117146 A061553 A138934 * A065386 A048951 A058629` `Adjacent sequences: A008761 A008762 A008763 * A008765 A008766 A008767`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`
	EXTENSIONS	`Better description and more terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 06 2000`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 20:03 EST 2012. Contains 205852 sequences.