cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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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.

Original entry on oeis.org

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

Views

Author

Pontus von Brömssen, Aug 14 2025

Keywords

Examples

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

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).

A387005 Number of free (d,2)-polyominoids of size n in arbitrary dimension d.

Original entry on oeis.org

1, 2, 12, 103
Offset: 1

Views

Author

Pontus von Brömssen, Aug 14 2025

Keywords

Crossrefs

Main diagonal of A387003.
Row sums of A387004.
Cf. A005519 (polyominoes), A365565 (polysticks).
Cf. A000105 (2 dimensions), A075679 (3 dimensions), A366334 (4 dimensions).
Showing 1-2 of 2 results.