Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

A318062

Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

Terms

    a(0) =1a(1) =5a(2) =18a(3) =67a(4) =249a(5) =925a(6) =3437a(7) =12770a(8) =47447a(9) =176289a(10) =655001a(11) =2433653a(12) =9042226a(13) =33596347a(14) =124827065a(15) =463794357a(16) =1723225693a(17) =6402636738a(18) =23788965871a(19) =88387787777a(20) =328404398513

External references