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 1-4 of 4 results.

A125679 Erroneous version of A108239.

Original entry on oeis.org

9, 44, 655, 42426, 11590894, 12561206794
Offset: 7

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Author

Jonathan Vos Post, Jan 30 2007

Keywords

Comments

Old name was: Number of combinatorial 2-manifolds with n vertices.
The reference includes disconnected manifolds into the count for n = 8 but not for n > 8, hence assembling these numbers into a single sequence is nonsensical. - Andrey Zabolotskiy, Sep 21 2021

A005026 Number of non-neighborly combinatorial 3-manifolds.

Original entry on oeis.org

1, 4, 35, 1246
Offset: 6

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A108239.

Extensions

"non-neighborly" inserted into name by Andrey Zabolotskiy, Sep 21 2021

A135327 Number of genus-surfaces with n vertices.

Original entry on oeis.org

1, 0, 1, 3, 21, 586, 50531, 16141671
Offset: 3

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Author

Jonathan Vos Post, Dec 06 2007

Keywords

Examples

			a(3) = 1 because the unique surface with 3 vertices is on the closed surface S^2.
a(4) = 0 because there are no surface with 4 vertices in Amendola's table.
a(5) = 1 because the unique surface with 5 vertices is on the closed surface RP^2.
a(6) = 3 because there is a unique surface with 6 vertices on the closed surface T^2 and two on RP^2, so 1 + 2 = 3.
a(7) = 21 because there are 5 surfaces with 7 vertices on the closed surface T^2, 6 on RP^2 and 10 on K^2, so 5 + 6 + 10 = 21.
a(8) = 46 + 11 + 108 + 284 + 134 + 3 = 586 (see table).
a(9) = 230 + 1261 + 59 + 28 + 597 + 6919 + 18166 + 18199 + 4994 + 78 = 50531 (see table).
a(10) = 1513 + 50878 + 99177 + 3892 + 356 + 3864 + 82588 + 713714 + 3006044 + 5672821 + 4999850 + 1453490 + 53484 = 16141671.
		

Crossrefs

Cf. A108239.

Extensions

Edited by N. J. A. Sloane, Dec 07 2007
Missing a(5) = 1 inserted by Andrey Zabolotskiy, Nov 20 2017
Name corrected by Andrey Zabolotskiy, Sep 21 2021

A143725 Numbers of non-orientable triangulated surfaces with 12 vertices and genus n.

Original entry on oeis.org

114478, 1448516, 16306649, 99694693, 473864807, 1479135833, 3117091975, 3935668832, 2627619810, 711868010, 49305639, 182200
Offset: 1

Views

Author

Jonathan Vos Post, Aug 29 2008

Keywords

Crossrefs

Cf. A108239.
Showing 1-4 of 4 results.