1/3 the number of (n+1)X6 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

A184372

1/3 the number of (n+1)X6 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Terms

    a(0) =58077a(1) =15754461a(2) =4210059673

External references