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

A146021

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

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =17a(7) =33a(8) =77a(9) =271a(10) =971a(11) =3963a(12) =20443a(13) =99229a(14) =615963a(15) =4003277a(16) =33415251a(17) =283218519a(18) =3003051651a(19) =32410844251a(20) =438884364075

External references