A052280 Number of 4 X 4 stochastic matrices under row and column permutations.

1, 1, 5, 12, 43, 106, 321, 787, 1960, 4354, 9386, 18790, 36362, 66789, 118936, 203840, 340195, 551192, 873343, 1351457, 2052221, 3056798, 4480565, 6462678, 9194098, 12902867, 17892986, 24524478, 33265476, 44666016, 59426834, 78364873, 102502765, 133024660, 171390035, 219278224

Offset

0,3

Links

Table of n, a(n) for n=0..35.

Example

There are 5 nonisomorphic 4 X 4 matrices with row and column sums 2:
[0 0 0 2] [0 0 0 2] [0 0 0 2] [0 0 1 1] [0 0 1 1]
[0 0 2 0] [0 0 2 0] [0 1 1 0] [0 0 1 1] [0 1 0 1]
[0 2 0 0] [1 1 0 0] [1 0 1 0] [1 1 0 0] [1 0 1 0]
[2 0 0 0] [1 1 0 0] [1 1 0 0] [1 1 0 0] [1 1 0 0]

Crossrefs

Row n=4 of A333733.

Cf. A001496, A052281, A052282.

Sequence in context: A129795 A187916 A052644 * A195541 A006078 A046612

Adjacent sequences: A052277 A052278 A052279 * A052281 A052282 A052283

Keyword

nonn

Author

Vladeta Jovovic, Feb 06 2000

Extensions

Terms a(9) and beyond from Andrew Howroyd, Apr 04 2020

Status

approved