Number of 2 X n 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.
A268972
Number of 2 X n 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.
Terms
- a(0) =9a(1) =60a(2) =240a(3) =912a(4) =3312a(5) =11664a(6) =40176a(7) =136080a(8) =454896a(9) =1504656a(10) =4933872a(11) =16061328a(12) =51963120a(13) =167226768a(14) =535692528a(15) =1709114256a(16) =5433452784a(17) =17218688400a(18) =54411055344a(19) =171498136464a(20) =539289320688
External references
- oeis: A268972