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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A292065 Number of Besźel [Beszel] Polycubes with n cells, distinguishing mirror images. A Besźel polycube is a polycube whose cells each have two or more even coordinates.

Original entry on oeis.org

1, 1, 2, 4, 12, 27, 106, 339, 1336, 5029
Offset: 1

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Author

George Sicherman, Sep 08 2017

Keywords

Comments

This sequence also gives the number of Ul Qoma Polycubes with n cells. An Ul Qoma polycube is a polycube whose cells each have two or more odd coordinates.

Examples

			a(4) = 4 because 4 of the 8 tetracubes (I, L, T, K) can be embedded in the Besźel section of the cubic grid.
		

References

  • China Miéville, The City & the City, Macmillan, 2009.

Crossrefs

Cf. A292157: Number of Besźel Polycubes with n cells, identifying mirror images; A000162: Number of polycubes with n cells [distinguishing mirror images].

A294151 Number of perforated polyominoes with n cells, identifying mirror images.

Original entry on oeis.org

1, 1, 2, 3, 8, 13, 36, 76, 202, 482, 1281, 3277, 8749, 23083, 62056, 166498, 450576, 1220542, 3321870, 9057388, 24769906
Offset: 1

Views

Author

George Sicherman, Oct 23 2017

Keywords

Comments

A perforated polyomino is a polyomino in which every cell has at least one even coordinate.

Examples

			a(4)=3 because there are 5 tetrominoes, and the skew and square tetrominoes do not lie in the perforated grid, which leaves 3.
		

Crossrefs

Cf. A000105, number of polyominoes with n cells; A292065, number of Besźel Polycubes with n cells, distinguishing mirror images; A292157, same but identifying mirror images.

Extensions

a(16) - a(21) from Joerg Arndt, Dec 11 2023
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