1/36 the number of (n+2) X 3 0..2 arrays with each 3 X 3 subblock containing two of one value, two of another, and five of the last.

A184449

1/36 the number of (n+2) X 3 0..2 arrays with each 3 X 3 subblock containing two of one value, two of another, and five of the last.

Terms

    a(0) =63a(1) =234a(2) =864a(3) =3159a(4) =12879a(5) =51759a(6) =203391a(7) =898857a(8) =3877551a(9) =16120377a(10) =75287475a(11) =340653681a(12) =1468371483a(13) =7083577089a(14) =32959439379a(15) =145024403049a(16) =711949718619

External references