Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

A146043

Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =5a(11) =5a(12) =21a(13) =21a(14) =83a(15) =83a(16) =385a(17) =385a(18) =2131a(19) =2131a(20) =24025a(21) =24025a(22) =318135a(23) =318135a(24) =5078109a(25) =5078109a(26) =98561015

External references