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.

A383799 Irregular triangle: T(n,k) gives the number of k-polysticks on edges of the n-cube up to rotational symmetries of the n-cube, with 0 <= k <= A001787(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 6, 14, 24, 32, 25, 13, 5, 1, 1, 1, 1, 1, 4, 10, 35, 131, 510, 1932, 7123, 24466, 76829, 214685, 518820, 1050433, 1727591, 2273998, 2446653, 2212119, 1709579, 1143416, 663450, 335186, 146371, 55327, 17767, 4898, 1103, 226, 35, 7, 1, 1
Offset: 1

Views

Author

Peter Kagey, May 10 2025

Keywords

Comments

Row 3 gives the number of polyforms with n cells on the faces of a rhombic dodecahedron up to rotation.

Examples

			Table begins:
n\k| 0  1  2  3   4   5    6    7     8     9     10     11      12
---+----------------------------------------------------------------
  1| 1, 1;
  2| 1, 1, 1, 1,  1;
  3| 1, 1, 1, 4,  6, 14,  24,  32,   25,   13,     5,     1,      1;
  4| 1, 1, 1, 4, 10, 35, 131, 510, 1932, 7123, 24466, 76829, 214685, ...
		

Crossrefs

Cf. A333333 (analogous with reflectional symmetries allowed).

Formula

A222186(n) = Sum_{k=0..n*2^(n-1)} T(n,k) - Sum_{k=0..(n-1)*2^(n-2)} T(n-1,k) for n >= 2. - Pontus von Brömssen, May 12 2025

Extensions

a(30)-a(40) from Pontus von Brömssen, May 14 2025
a(41)-a(53) from Pontus von Brömssen, Jun 11 2025

A222192 a(n) = number of inequivalent ways to choose a subset of the n*2^(n-1) edges of the n-cube so that the resulting figure is connected and fully n-dimensional.

Original entry on oeis.org

1, 3, 78, 7338218
Offset: 1

Views

Author

Andrew Weimholt, Feb 12 2013

Keywords

Comments

"Inequivalent" means that figures differing by a rotation and/or reflection are not regarded as different.
"Fully n-dimensional" means not lying in a proper subspace.
This is a variation on A222186, that was based on a work by the artist Sol LeWitt.

Examples

			For n=2 the three figures are: the four edges of a square, or omit one edge, or omit two adjacent edges.
		

Crossrefs

Cf. A222186.

Extensions

a(4) computed by Andrew Weimholt, Feb 13 2013
Showing 1-2 of 2 results.