A247417 Number of nonisomorphic binary n X n matrices with two 1's per column under row and column permutations.

1, 3, 11, 35, 132, 471, 1806, 7042, 28494, 118662, 510517, 2262738, 10337474, 48625631, 235357470, 1171163995, 5986424739, 31403695142, 168913667164, 930739116386, 5249162406890, 30275048671498, 178428441191289, 1073737691984694, 6592909590432719

Offset: 2

Author

Marko Riedel, Sep 21 2014

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 2..50
• Marko Riedel, MAPLE Cycle Indices and Burnside Computation for Non-Isomorphic N by N binary matrices with K entries per column under row and column permutation
• StackExchange, How many arrays with crossed cells, order of rows/columns irrelevant, Dec 13 2013

Crossrefs

Column k=2 of A304942.

Cf. A247596, A247597, A247598.

Programs

Maple

Using the uploaded program the call is seq(matrix_marks(n,2), n=3..15);

PARI

\\ See A304942 for Blocks
a(n) = Blocks(n, n, 2); \\ Andrew Howroyd, May 24 2018

Extensions

Terms a(17) and beyond from Andrew Howroyd, May 23 2018