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.

Showing 1-2 of 2 results.

A359520 Number of free holey polyominoes of n cells with simply-connected interiors.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 5, 35, 179, 909, 4285, 19702, 88040, 386826, 1674852, 7174436, 30462009
Offset: 1

Views

Author

John Mason, Jan 04 2023

Keywords

Examples

			a(7) = 1 because of the holey heptomino.

Crossrefs

Cf. A000104, A000105, A001419, A342537, A359519.

Formula

a(n) = A342537(n) - A000104(n) (simply connected polyominoes minus unholey polyominoes).

A359523 Number of free polyiamonds of n cells with multiply-connected interiors.

Original entry on oeis.org

1, 2, 12, 51, 217, 846, 3211
Offset: 12

Views

Author

John Mason, Jan 05 2023

Keywords

Crossrefs

Cf. A000577, A070764, A359519, A359524.

Formula

a(n) = A070764(n) - A359524(n).
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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