A387004 Triangle read by rows: T(n,d) is the number of free, properly d-dimensional (d,2)-polyominoids of size n, 2 <= d <= n+1.

1, 1, 1, 2, 7, 3, 5, 49, 41, 8

Offset: 1

Author

Pontus von Brömssen, Aug 14 2025

Keywords

• nonn
• tabl
• more

Examples

			Triangle begins:
  n\d| 2  3  4  5
  ---+-----------
  1  | 1
  2  | 1  1
  3  | 2  7  3
  4  | 5 49 41  8
		

Links

• Wikipedia, Polyominoid.
• Index entries for sequences related to polyominoes.

Crossrefs

Cf. A000105 (column d=2), A049430 (polyominoes), A365566 (polysticks), A387002 (fixed), A387003, A387005 (row sums).

Formula

T(n,d) = A387003(n,d) - A387003(n,d-1) (with A387003(n,1) = 0).