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

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.

Terms

    a(0) =1a(1) =2a(2) =1a(3) =3a(4) =4a(5) =13a(6) =17a(7) =82a(8) =167a(9) =1029a(10) =2594a(11) =22033a(12) =77729a(13) =874498a(14) =4050975a(15) =61638683a(16) =387821570a(17) =7893076251a(18) =66271702355

External references