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.

A057784 Number of polypons with n cells.

Original entry on oeis.org

1, 2, 2, 4, 4, 10, 13, 29, 47, 100, 181, 383, 738, 1539, 3087, 6419, 13135, 27402, 56779, 118876, 248384, 521850, 1096261, 2310793, 4874305, 10305560, 21810868, 46239224
Offset: 1

Views

Author

N. J. A. Sloane, Nov 04 2000

Keywords

Comments

A polypon is a polyform made up of 30-30-120 triangles from the [3.12^2] Laves tiling, joined along their edges. Because that tiling contains hexagons formed as a union of six triangles, with the division of the hexagon having less symmetry than the hexagon on its own, some polypons can be divided into their constituent triangles in more than one way, and whether the division is significant affects the values of a(n) when n >= 18 is a multiple of 6. For the present sequence, the division into triangles is considered significant. - Joseph Myers, Oct 02 2011

References

  • Computed by Brendan Owen.

Links

Crossrefs

Cf. A355562, A151531, A151532, A151533.

Extensions

Link updated by William Rex Marshall, Dec 16 2009
a(21)-a(26) from Joseph Myers, Oct 02 2011
a(27)-a(28) from Sean A. Irvine, Jul 04 2022

A196993 Number of fixed polypons with n cells (division into triangles is significant).

Original entry on oeis.org

6, 9, 14, 24, 42, 77, 144, 276, 538, 1065, 2136, 4321, 8790, 17967, 36890, 76050, 157380, 326824, 680880, 1422570, 2979572, 6254175, 13153242, 27712901, 58487796, 123632910, 261722022, 554800719, 1177553610, 2502256578, 5322993522
Offset: 1

Views

Author

Joseph Myers, Oct 08 2011

Keywords

Links

  • Eric Weisstein's World of Mathematics, Polypon

Crossrefs

Cf. A057784, A151531, A151532, A151533.

Extensions

a(27)-a(31) from Johann Peters, Dec 16 2024

A151531 Number of 1-sided polypons with n cells.

Original entry on oeis.org

1, 2, 3, 5, 7, 15, 24, 49, 91, 183, 356, 734, 1465, 3017, 6153, 12721, 26230, 54575, 113480, 237296, 496612, 1042785, 2192207, 4619736, 9747966, 20607348
Offset: 1

Views

Author

Ed Pegg Jr, May 13 2009

Keywords

Comments

The division of a polypon into triangles is considered significant for this sequence, as for A057784. - Joseph Myers, Oct 02 2011

Links

Crossrefs

Cf. A057784, A151532, A151533.

Extensions

a(19)-a(26) from Joseph Myers, Oct 02 2011

A151532 Number of 1-sided strip polypons with n cells.

Original entry on oeis.org

1, 2, 2, 4, 4, 7, 8, 14, 16, 26, 32, 50, 60, 93, 116, 180, 224, 340, 432, 646, 812, 1215, 1552, 2314, 2944, 4371, 5592, 8252, 10520, 15558, 19928, 29370, 37512, 55318, 70800, 104042, 132900, 195685, 250336, 367662, 469536, 690584, 882664, 1295126, 1653128, 2429594
Offset: 1

Views

Author

Ed Pegg Jr, May 13 2009

Keywords

Links

Crossrefs

Cf. A057784, A151531, A151533.

Extensions

a(21)-a(46) from Joseph Myers, Oct 02 2011
Showing 1-4 of 4 results.

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

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