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.

Previous Showing 11-19 of 19 results.

A343959 a(n) is the number of decagonal faces of Johnson solid J_n.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 10, 10, 9, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Felix Fröhlich, May 05 2021

Keywords

Crossrefs

Formula

a(n) < A242731(n).

Extensions

a(87)-a(92) from Pontus von Brömssen, May 27 2025

A296602 Values of F for which there is a unique convex polyhedron with F faces that are all regular polygons.

Original entry on oeis.org

4, 19, 23, 25, 29, 31, 33, 35, 39, 41, 43, 45, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171, 173
Offset: 1

Views

Author

Jonathan Sondow, Jan 28 2018

Keywords

Comments

The main entry for this sequence is A180916.
All terms except 4 are odd, because both the cube and the pentagonal pyramid have 6 faces, and for any even F > 6 both a prism and an antiprism can have F faces. Platonic solids, Archimedean solids, Johnson solids, and prisms account for the missing odd numbers.

Examples

			The regular tetrahedron is the only convex polyhedron with 4 faces that are all regular polygons, and no such polyhedron with fewer than 4 faces exists, so a(1) = 4.
		

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{2, -1}, {4, 19, 23, 25, 29, 31, 33, 35, 39, 41, 43, 45, 49, 51}, 30] (* Georg Fischer, Oct 26 2020 *)

Formula

A180916(a(n)) = 1.
From Colin Barker, Jul 05 2020: (Start)
G.f.: x*(4 + 11*x - 11*x^2 - 2*x^3 + 2*x^4 - 2*x^5 + 2*x^8 - 2*x^9 + 2*x^12 - 2*x^13) / (1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) for n>14.
(End)

A343209 Number of spanning trees of the graph of the n-th Johnson solid.

Original entry on oeis.org

45, 121, 1815, 24000, 297025, 78250050, 361, 3509, 30976, 27216, 403202, 75, 1805, 1728, 31500, 508805, 207368, 1609152, 227402340, 29821320745, 8223103375490, 37158912, 15482880000, 5996600870820, 1702422879696000, 1176, 324900, 29859840, 30950832, 2518646460
Offset: 1

Views

Author

Pontus von Brömssen, Apr 08 2021

Keywords

Comments

Terms are taken from the paper by Horiyama and Shoji, verified by Pontus von Brömssen.

Examples

			The gyrobifastigium (J26) has a(26) = 1176 spanning trees.
		

Crossrefs

A343210 Number of nonisomorphic unfoldings of the n-th Johnson solid.

Original entry on oeis.org

8, 15, 308, 3030, 29757, 7825005, 63, 448, 3116, 3421, 40321, 9, 99, 156, 2010, 25574, 13041, 268260, 28427091, 2982139245, 822310337549, 6193152, 1935360000, 599660087082, 170242287969600, 152, 27195, 1867560, 1934427, 125939163, 132627603, 74520844992
Offset: 1

Views

Author

Pontus von Brömssen, Apr 08 2021

Keywords

Comments

Unfoldings with overlaps are allowed.
Terms are taken from the paper by Horiyama and Shoji.

Examples

			The gyrobifastigium (J26) has a(26) = 152 nonisomorphic unfoldings.
		

Crossrefs

A343211 Number of (undirected) Hamiltonian cycles of the graph of the n-th Johnson solid.

Original entry on oeis.org

4, 5, 7, 11, 16, 90, 6, 16, 30, 80, 240, 6, 30, 12, 52, 160, 268, 67, 225, 716, 3550, 794, 6228, 44092, 194620, 9, 96, 396, 361, 1350, 1296, 6560, 6520, 32560, 708, 718, 6033, 45625, 45856, 221970, 221680, 1083340, 1082370, 8422, 162301, 2751301, 12817980
Offset: 1

Views

Author

Pontus von Brömssen, Apr 08 2021

Keywords

Examples

			The gyrobifastigium (J26) has a(26) = 9 Hamiltonian cycles.
		

Crossrefs

A299114 Number of sides of a face of an Archimedean solid.

Original entry on oeis.org

3, 4, 5, 6, 8, 10
Offset: 1

Views

Author

Jonathan Sondow, Feb 02 2018

Keywords

Comments

Values of n for which the regular n-gon is a face of some Archimedean solid.
Remarkably, the same is true for Johnson solids. Indeed, before Johnson (1966) and Zalgaller (1967) classified the 92 Johnson solids, Grünbaum and Johnson (1965) proved that the only polygons that occur as faces of a non-uniform regular-faced convex polyhedron (i.e., a Johnson solid) are triangles, squares, pentagons, hexagons, octagons, and decagons.

Crossrefs

A306949 a(n) is the number of different types of faces of Johnson solid J_n, with solids ordered by indices in Johnson's paper.

Original entry on oeis.org

2, 2, 3, 3, 4, 3, 2, 2, 3, 2, 2, 1, 1, 2, 2, 2, 1, 3, 3, 4, 4, 3, 3, 4, 3, 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 2, 2, 2, 1, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 1, 2, 2, 2, 2, 2, 2, 3, 4
Offset: 1

Views

Author

Felix Fröhlich, Mar 17 2019

Keywords

Comments

A299529(x) equals the number of times the value x occurs as a term in this sequence. In particular, if A299529(x) = 0, then x does not occur in this sequence.

Examples

			For n = 5: Johnson solid J_5 is the pentagonal cupola. This solid is bounded by 5 equilateral triangles, 5 squares, 1 pentagon and 1 decagon. Thus, there are 4 types of polygons making up the faces of this solid, hence a(5) = 4.
		

References

  • V. A. Zalgaller, Convex Polyhedra with Regular Faces, in: Seminars in mathematics, Springer, 1969, ISBN 978-1-4899-5671-2.

Crossrefs

Extensions

a(68) corrected and a(88)-a(92) added by Pontus von Brömssen, Mar 13 2021

A343212 Order of the symmetry group of the n-th Johnson solid.

Original entry on oeis.org

8, 10, 6, 8, 10, 10, 6, 8, 10, 8, 10, 12, 20, 12, 16, 20, 16, 6, 8, 10, 10, 6, 8, 10, 10, 8, 12, 16, 16, 20, 20, 10, 10, 20, 12, 12, 16, 20, 20, 10, 10, 20, 20, 6, 8, 10, 5, 10, 4, 4, 12, 4, 4, 4, 8, 4, 12, 10, 20, 4, 6, 4, 6, 6, 6, 8, 16, 10, 20, 4, 6, 10, 20, 4, 6, 10, 10, 2, 2, 20, 4, 2, 6, 8, 16, 4, 2, 4, 4, 8, 8, 6
Offset: 1

Views

Author

Pontus von Brömssen, Apr 08 2021

Keywords

Examples

			The gyrobifastigium (J26) has a(26) = 8 symmetries.
		

Crossrefs

A343961 a(n) is the number of Johnson solids of unit edge length with a volume V such that n <= V < n+1.

Original entry on oeis.org

10, 15, 9, 9, 5, 1, 3, 1, 5, 3, 1, 1, 2, 2, 1, 2, 2, 1, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 3, 0, 0, 4, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 0

Views

Author

Felix Fröhlich, May 05 2021

Keywords

Comments

a(n) = 0 for n > 92.

Examples

			For n = 6: The Johnson solids with volumes V with 6 <= V < 7 are J_6, J_19 and J_23 with V ~ 6.21, 6.77 and 6.92, respectively, so a(6) = 3.
		

Crossrefs

Previous Showing 11-19 of 19 results.