A141485 Number of n X n binary matrices, symmetric about both diagonal and antidiagonal, with no more than 1 one in any 2 X 2 subblock.

1, 2, 1, 5, 4, 21, 21, 158, 225, 2181, 4032, 53517, 135895, 2389270, 8052775, 191382781, 871834816, 27710789575, 168906089337, 7222686132766, 59221019073815, 3396328221185505, 37352381844672086, 2877824684844515547

Offset

0,2

Links

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

Crossrefs

Sequence in context: A346800 A124660 A217104 * A005605 A300661 A145882

Adjacent sequences: A141482 A141483 A141484 * A141486 A141487 A141488

Keyword

nonn

Author

R. H. Hardin, Aug 09 2008

Status

approved