A141487 Number of n X n binary matrices, symmetric under 90-degree rotation, with no more than 1 one in any 2 X 2 subblock.

1, 2, 1, 3, 4, 13, 17, 82, 167, 1029, 2594, 22033, 77729, 874498, 4050975, 61638683, 387821570, 7893076251, 66271702355, 1814566347320, 20521356444643, 753627817663469, 11423997447177546, 563598221301212705

Offset

0,2

Links

R. H. Hardin, Aug 09 2008, Table of n, a(n) for n = 0..30

Crossrefs

Sequence in context: A001054 A375364 A218209 * A217103 A099866 A365228

Adjacent sequences: A141484 A141485 A141486 * A141488 A141489 A141490

Keyword

nonn

Author

R. H. Hardin, Aug 09 2008

Status

approved