Number of n X n binary matrices, symmetric about the diagonal and under 90-degree rotation, with no more than 3 ones in any 2 X 2 subblock.

A141512

Number of n X n binary matrices, symmetric about the diagonal and under 90-degree rotation, with no more than 3 ones in any 2 X 2 subblock.

Terms

    a(0) =1a(1) =2a(2) =1a(3) =7a(4) =4a(5) =49a(6) =21a(7) =648a(8) =245a(9) =16475a(10) =5184a(11) =801489a(12) =214175a(13) =74700792a(14) =16831269a(15) =13333992705a(16) =2539826928a(18) =733369598775

External references