Number of 2-cell columns in all deco polyominoes of height n. A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.
A121639
Number of 2-cell columns in all deco polyominoes of height n. A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.
Terms
- a(0) =0a(1) =1a(2) =5a(3) =25a(4) =147a(5) =996a(6) =7668a(7) =66264a(8) =635976a(9) =6717600a(10) =77482080a(11) =969338880a(12) =13076778240a(13) =189261999360
External references
- oeis: A121639