A141508 Number of n X n binary matrices, symmetric under 180 degree rotation, with no more than 2 ones in any 2 X 2 subblock.

1, 2, 3, 19, 93, 1575, 21225, 1007325, 39296735, 5294789855, 584025270873, 223173910768577, 70041418150889563, 76024730608891641301, 67725956302664583147084, 208747768532396398250753135, 528233319697505378983008951127

Offset

0,2

Links

Table of n, a(n) for n=0..16.

Crossrefs

Sequence in context: A262957 A072263 A009178 * A366357 A119344 A072877

Adjacent sequences: A141505 A141506 A141507 * A141509 A141510 A141511

Keyword

nonn

Author

R. H. Hardin, Aug 10 2008

Status

approved