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 1-5 of 5 results.

A019503 Simplexity of the n-cube: minimal cardinality of triangulation of n-cube using n-simplices whose vertices are vertices of the n-cube.

Original entry on oeis.org

1, 2, 5, 16, 67, 308, 1493
Offset: 1

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Author

Keywords

Comments

5522 <= a(8) <= 11944 [Haiman, Ziegler]. - Jonathan Vos Post, Jul 13 2005

References

  • H. T. Croft, K. J. Falconer and R. K. Guy, Unsolved Problems in Geometry, C9.
  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 8.9, p. 512.
  • Warren D. Smith, Lower bounds for triangulations of the N-cube, manuscript, 1994.
  • Gunter M. Ziegler, Lectures on Polytopes, Revised First Edn., Graduate Texts in Mathematics, Springer, 1994, p. 147.

Crossrefs

Other sequences dealing with different ways to attack this problem. They give further references: A019502, A019504, A166932, A166932, A239912, A275518.

A019502 Number of simplices in minimal decomposition of an n-cube.

Original entry on oeis.org

1, 2, 5, 16, 67
Offset: 1

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Author

Keywords

References

  • H. T. Croft, K. J. Falconer and R. K. Guy, Unsolved Problems in Geometry, Section C9.
  • R. K. Guy, What is the simplexity of the d-cube?, Amer. Math. Monthly, 91:10 (1984), 628-629.

Crossrefs

Other sequences dealing with different ways to attack this problem. They give further references: A019503, A019504, A166932, A166932, A239912, A275518.
See also A094294, A238820, A238821.

A275518 Number of simplices in corner-cut triangulation of the n-cube.

Original entry on oeis.org

1, 2, 5, 16, 67, 364, 2445, 19296, 173015, 1728604, 19011049, 228124384, 2965598547, 41518338684, 622774990133, 9964399645504, 169394793547567, 3049106282938684, 57933019373868897, 1158660387473183616, 24331868136927943019, 535301099012395872028
Offset: 1

Views

Author

R. J. Mathar, Jul 31 2016

Keywords

Comments

This corrects the value of a(10) in A239911 published by Sallee in Discr. Math. 40. The correct value is for example given by Lee.

Crossrefs

Programs

  • Maple
    p := proc(d,x)
        add( x^i/i!,i=0..d) ;
    end proc:
    A275518 := proc(d)
        d!*(p(d,2)/2-p(d,1))+2^(d-1)-d!/2+1 ;
    end proc:
    seq(A275518(d),d=1..18) ;
  • Mathematica
    p[d_, x_] := Sum[x^i/i!, {i, 0, d}];
    A275518[d_] := d!*(p[d, 2]/2 - p[d, 1]) + 2^(d - 1) - d!/2 + 1;
    Table[A275518[d], {d, 1, 18}] (* Jean-François Alcover, Sep 06 2023, after Maple program *)
  • PARI
    a(n) = 1 + 2^(n-1) - n! + n!*sum(i=1, n, (2^(i-1)-1)/i!) \\ Andrew Howroyd, Sep 06 2023

Formula

a(n) = 1 + 2^(n-1) - n! + n!*Sum_{i=1..n} (2^(i-1)-1)/i!. - Andrew Howroyd, Sep 06 2023, after Maple program

Extensions

Terms a(19) and beyond from Andrew Howroyd, Sep 06 2023

A239912 Number of simplices is middle-cut slicing of n-cube.

Original entry on oeis.org

1, 2, 5, 16, 67, 324, 1962, 13248, 106181, 931300
Offset: 1

Views

Author

N. J. A. Sloane, Apr 09 2014

Keywords

Crossrefs

Other sequences dealing with different ways to attack this problem. They give further references: A019502, A019503, A019504, A166932, A166932, A275518.

A239911 Erroneous version of A275518.

Original entry on oeis.org

1, 2, 5, 16, 67, 364, 2445, 19296, 173015, 1720924
Offset: 1

Views

Author

N. J. A. Sloane, Apr 09 2014

Keywords

References

  • Sallee, John F. A note on minimal triangulations of an n-cube. Discrete Appl. Math. 4 (1982), no. 3, 211--215. MR0675850 (84g:52019)
  • Sallee, John F. The middle-cut triangulations of the n-cube. SIAM J. Algebraic Discrete Methods 5 (1984), no. 3, 407--419. MR0752044 (86c:05054). See Table 2.

Crossrefs

Showing 1-5 of 5 results.