Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.

A146060

Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =5a(6) =15a(7) =27a(8) =53a(9) =153a(10) =487a(11) =1719a(12) =7415a(13) =32545a(14) =166197a(15) =903303a(16) =5463687a(17) =37085195a(18) =288519629a(19) =2455679981a(20) =24371430209a(21) =259645240127

External references