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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A058787 Triangle T(n,k) = number of polyhedra (triconnected planar graphs) with n faces and k vertices, where (n/2+2) <= k <= (2n+8).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 2, 8, 11, 8, 5, 2, 11, 42, 74, 76, 38, 14, 8, 74, 296, 633, 768, 558, 219, 50, 5, 76, 633, 2635, 6134, 8822, 7916, 4442, 1404, 233, 38, 768, 6134, 25626, 64439, 104213, 112082, 79773, 36528, 9714, 1249, 14, 558, 8822, 64439, 268394, 709302
Offset: 4

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Author

Gerard P. Michon, Nov 29 2000

Keywords

Comments

Rows are of lengths 1, 2, 4, 5, 7, 8, 10, 11, 13, 14, ... floor(3n/2)-5. See A001651 (this is the sequence of integers not divisible by 3).

Examples

			There are 38 polyhedra with 9 faces and 11 vertices, or with 11 faces and 9 vertices.
		

Crossrefs

A049337, A058787, A212438 are all versions of the same triangle.

A279015 Greatest possible number of diagonals of a polyhedron having n faces.

Original entry on oeis.org

0, 0, 4, 10, 20, 34, 52, 73, 100, 128, 162, 199, 240, 285, 334, 387, 444, 505, 570, 639, 712, 789, 870, 955, 1044, 1137, 1234, 1335, 1440, 1549, 1662, 1779, 1900, 2025, 2154, 2287, 2424, 2565, 2710, 2859, 3012, 3169, 3330, 3495, 3664, 3837, 4014, 4195, 4380, 4569
Offset: 4

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Author

Vladimir Letsko, Dec 03 2016

Keywords

Comments

Also the greatest possible number of diagonals of a simple polyhedron with n faces. In other words, a polyhedron with n faces having the greatest possible number of diagonals must be a simple one.

Examples

			a(6)=4 because 6 is the greatest possible number of diagonals of a hexahedron.
		

Crossrefs

Programs

  • Maple
    F:=n->piecewise(4<=n and n<=5,0,6<=n and n<=10,2*n^2-20*n+52,n=11,73,n=13,128,n=12 or n>=14,2*n^2-21*n+64);
  • Mathematica
    Drop[#, 4] &@ CoefficientList[Series[x^6*(4 - 2 x + 2 x^2 - x^5 + 3 x^6 - 5 x^7 + 5 x^8 - 3 x^9 + x^10)/(1 - x)^3, {x, 0, 53}], x] (* Michael De Vlieger, Dec 05 2016 *)
  • PARI
    concat(vector(2), Vec(x^6*(4 - 2*x + 2*x^2 - x^5 + 3*x^6 - 5*x^7 + 5*x^8 - 3*x^9 + x^10) / (1 - x)^3 + O(x^30))) \\ Colin Barker, Dec 05 2016

Formula

a(n) = 2*n^2 - 21*n + 64 for n=12 or n>=14.
From Colin Barker, Dec 05 2016: (Start)
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>8.
G.f.: x^6*(4 - 2*x + 2*x^2 - x^5 + 3*x^6 - 5*x^7 + 5*x^8 - 3*x^9 + x^10) / (1 - x)^3.
(End)

A058786 Number of n-hedra with 2n-5 vertices or 3n-7 edges (the vertices of these are all of degree 3, except one which is of degree 4). Alternatively, the number of polyhedra with n vertices whose faces are all triangular, except one which is tetragonal.

Original entry on oeis.org

1, 2, 8, 38, 219, 1404, 9714, 70454, 527235, 4037671, 31477887, 249026400, 1994599707, 16147744792, 131959532817, 1087376999834, 9027039627035, 75441790558926, 634311771606750, 5362639252793358, 45565021714371644, 388937603694422120, 3333984869758146814
Offset: 5

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Author

Gerard P. Michon, Nov 29 2000

Keywords

Examples

			a(5)=1 because the square pyramid is the only pentahedron with 5=2*5-5 vertices (or 8=3*5-7 edges). Alternatively, a(5)=1 because the square pyramid is the only polyhedron with 5 vertices whose faces are all triangles with only one tetragonal exception.
		

Crossrefs

Programs

Extensions

Terms a(19) and beyond from Andrew Howroyd, Feb 27 2021

A058788 Triangle T(n,k) = number of polyhedra (triconnected planar graphs) with n edges and k vertices (or k faces), where (n/3+2) <= k <= (2n/3). Note that there is no such k when n=7.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 2, 2, 8, 2, 11, 11, 8, 42, 8, 5, 74, 74, 5, 76, 296, 76, 38, 633, 633, 38, 14, 768, 2635, 768, 14, 558, 6134, 6134, 558, 219, 8822, 25626, 8822, 219, 50, 7916, 64439, 64439, 7916, 50, 4442, 104213, 268394, 104213, 4442, 1404, 112082, 709302, 709302, 112082, 1404, 233, 79773, 1263032, 2937495, 1263032, 79773, 233, 36528, 1556952, 8085725, 8085725, 1556952, 36528, 9714, 1338853, 15535572, 33310550
Offset: 6

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Author

Gerard P. Michon, Nov 29 2000

Keywords

Comments

Rows are of lengths 1,0,1,2,1,2,3,2,3,4,3,4,5,4,5,6,5, ... n-1-2*floor((n+2)/3). See A008611. Note the zero length, which means that there are no polyhedra with n=7 edges.

Examples

			There are 768 different polyhedra with 18 edges and 9 or 11 faces.
		

Crossrefs

A005841 Number of 4-dimensional polytopes with n vertices.

Original entry on oeis.org

1, 4, 31, 1294, 274148
Offset: 5

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Author

Keywords

References

  • H. T. Croft, K. J. Falconer and R. K. Guy, Unsolved Problems in Geometry, B15.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A000944.

Extensions

a(9), from the paper by M. Firshing, added by Jud McCranie, Jan 30 2020

A093478 Number of regular (finite but not necessarily convex) polytopes of full rank in n-dimensional space, or -1 if the number is infinite.

Original entry on oeis.org

1, 1, -1, 18, 34, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6
Offset: 0

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Author

N. J. A. Sloane, May 22 2004

Keywords

References

  • P. McMullen and E. Schulte, Abstract Regular Polytopes, Encyclopedia of Mathematics and its Applications, Vol. 92, Cambridge University Press, Cambridge, 2002.

Crossrefs

A093479 Number of regular (infinite) apeirotopes of full rank in n-dimensional space.

Original entry on oeis.org

0, 1, 6, 8, 18, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
Offset: 0

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Author

N. J. A. Sloane, May 22 2004

Keywords

References

  • P. McMullen, Regular polytopes of full rank, lecture at The Coxeter Legacy meeting, Toronto, 2004.
  • P. McMullen and E. Schulte, Abstract Regular Polytopes, Encyclopedia of Mathematics and its Applications, Vol. 92, Cambridge University Press, Cambridge, 2002.
  • P. McMullen and E. Schulte, Paper to appear in Discrete and Computational Geometry, 2004.

Crossrefs

A187927 Number of embeddings on the sphere of 2-connected planar graphs, minimum vertex degree 3, with n nodes.

Original entry on oeis.org

2, 13, 163, 2067, 30953, 486674, 7957459, 133344454, 2280001754, 39648557743, 699731146514, 12511186297320
Offset: 6

Views

Author

Stuart E Anderson, Mar 16 2011

Keywords

Comments

The graphs are exactly 2-connected, not at least 2-connected. The graphs were enumerated using plantri (by B.D. McKay & G. Brinkmann) for the purpose of finding compound perfect squared squares.

Crossrefs

Programs

  • plantri
    plantri -p -c2 -m3 -x -u -v n  ; or

Extensions

a(15)-a(17) from Lorenz Milla, Oct 08 2013

A002841 Number of 3-connected self-dual planar graphs with 2n edges.

Original entry on oeis.org

1, 1, 2, 6, 16, 50, 165, 554, 1908, 6667, 23556, 84048, 302404, 1095536, 3993623
Offset: 3

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Author

Keywords

Comments

Also number of self-dual polyhedra with n+1 vertices (and n+1 faces). - Franklin T. Adams-Watters, Dec 18 2006

References

  • M. B. Dillencourt, Polyhedra of small orders and their Hamiltonian properties. Tech. Rep. 92-91, Info. and Comp. Sci. Dept., Univ. Calif. Irvine, 1992.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A000944.

Extensions

Definition corrected by Gordon F. Royle, Dec 15 2005
a(14)-a(17) added by Jan Goedgebeur, Sep 16 2021

A049340 Triangle read by rows: T(n,k) is the number of planar graphs with n >= 1 nodes and 0 <= k <= binomial(n,2) edges, all degrees even.

Original entry on oeis.org

1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 2, 2, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 4, 4, 6, 5, 5, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 3, 4, 7, 9, 15, 17, 22, 14, 16, 5, 4, 0, 1, 0, 0, 0
Offset: 1

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Author

Keywords

Examples

			Triangle begins:
  1;
  1, 0;
  1, 0, 0, 1;
  1, 0, 0, 1, 1, 0, 0;
  1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0;
  1, 0, 0, 1, 1, 1, 3, 2, 2, 1, 1, 0, 1, 0, 0, 0;
  ...
		

Crossrefs

Rows sums give A049339.

Extensions

Entry revised by Sean A. Irvine, Jul 29 2021
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