Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010101 or 01010101.

A260011

Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010101 or 01010101.

Terms

    a(0) =209a(1) =578a(2) =2492a(3) =8450a(4) =25600a(5) =84050a(6) =292422a(7) =985608a(8) =3251280a(9) =10857800a(10) =36602762a(11) =122774450a(12) =410260884a(13) =1373718528a(14) =4607045940a(15) =15437704898a(16) =51696499120a(17) =173176718162a(18) =580275938368

External references