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

A184369

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

Terms

    a(0) =153a(1) =2755a(2) =49235a(3) =880781a(4) =15754461a(5) =281803871a(6) =5040682279a(7) =90163722073

External references