Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101.

A261378

Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00001011 00010101 or 01010101.

Terms

    a(0) =247a(1) =470a(2) =1714a(3) =5254a(4) =14312a(5) =42302a(6) =128998a(7) =377183a(8) =1099308a(9) =3261560a(10) =9647696a(11) =28358158a(12) =83587624a(13) =246835566a(14) =727709732a(15) =2144744412a(16) =6325797274a(17) =18656814748a(18) =55007382412a(19) =162201500248a(20) =478326263928

External references