A247597 Number of nonisomorphic binary n X n matrices with four 1's per column under row and column permutations.

1, 7, 132, 6178, 594203, 85820809, 16341829155, 3875736708590, 1112175913348040, 378860991866916370, 151006214911844288232, 69600017255860985666964, 36729204987785981237238642, 22003003913198378660826731007, 14851323097928973689736994569534

Offset

4,2

Links

Andrew Howroyd, Table of n, a(n) for n = 4..40

StackExchange, How many arrays with crossed cells, order of rows/columns irrelevant, Dec 13 2013

Maple

seq(matrix_marks(n, 4), n=3..15); # Using the uploaded program to A247417

Prog

(PARI) \\ See A304942 for Blocks
a(n) = Blocks(n, n, 4); \\ Andrew Howroyd, May 24 2018

Crossrefs

Column k=4 of A304942.

Cf. A247417, A247596, A247598.

Sequence in context: A028420 A220257 A220321 * A305955 A051832 A103050

Adjacent sequences: A247594 A247595 A247596 * A247598 A247599 A247600

Keyword

nonn

Author

Marko Riedel, Sep 21 2014

Extensions

Terms a(16) and beyond from Andrew Howroyd, May 24 2018

Status

approved