1/3 the number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

A184368

1/3 the number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

Terms

    a(0) =21a(1) =153a(2) =1107a(3) =8019a(4) =58077a(5) =420633a(6) =3046491a(7) =22064643a(8) =159806277a(9) =1157419449a(10) =8382773187a(11) =60713414163a(12) =439725443661

External references