Number of (n+2)X(3+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 or 00000011.

A259718

Number of (n+2)X(3+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 or 00000011.

Terms

    a(0) =140a(1) =228a(2) =568a(3) =1064a(4) =1244a(5) =2858a(6) =6092a(7) =8638a(8) =15640a(9) =34858a(10) =57256a(11) =94682a(12) =200008a(13) =364268a(14) =598252a(15) =1171728a(16) =2247716a(17) =3811864a(18) =7036700a(19) =13649110a(20) =24088156a(21) =43117388a(22) =82546000a(23) =150335226a(24) =267211096a(25) =500979428a(26) =928570300a(27) =1661448778

External references