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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A135807 Tenth column (k=9) of triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 0, 0, 220, 715, 16016, 180180, 2619760, 39503750, 642172960, 11111964864, 204016477080, 3959206825210, 80952590044480, 1739019535313720, 39150661649469744, 921633956154372175, 22640304292494917600
Offset: 0

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Author

Wolfdieter Lang, Jan 21 2008, Feb 22 2008

Keywords

Comments

a(n) enumerates circular permutations of {1,2,...,n+9} with exactly nine successor pairs (i,i+1). Due to cyclicity also (n+9,1) is a successor pair.

Examples

			a(0)=1 because from the 9!/9 = 40320 circular permutations of n=9 elements only one, namely (1,2,3,4,5,6,7,8,9), has nine successors.
		

References

  • Ch. A. Charalambides, Enumerative Combinatorics, Chapman & Hall/CRC, Boca Raton, Florida, 2002, p. 183, eq. (5.15), for k=9.

Crossrefs

Cf. A135806 (column k=8).

Programs

  • Mathematica
    f[n_] := (-1)^n + Sum[(-1)^k*n!/((n - k)*k!), {k, 0, n - 1}]; a[n_, n_] = 1; a[n_, 0] := f[n]; a[n_, k_] := a[n, k] = n/k*a[n - 1, k - 1]; Table[a[n, 9], {n, 9, 25}] (* G. C. Greubel, Nov 10 2016 *)
  • PARI
    a(n)=((-1)^n + sum( k=0, n-1, (-1)^k * binomial( n, k) * (n - k - 1)!))*binomial(n+9,9) \\ Charles R Greathouse IV, Nov 10 2016

Formula

a(n) = binomial(n+9,9)*A000757(n), n>=0.
E.g.f.: (d^9/dx^9) (x^9/9!)*(1-log(1-x))/e^x.

A126352 Denominator of z-sequence for the Sheffer (Appell type) triangle A134832 (circular succession numbers).

Original entry on oeis.org

1, 1, 3, 4, 5, 3, 7, 8, 9, 1, 11, 12, 13, 7, 15, 16, 17, 9, 19, 4, 21, 11, 23, 24, 25, 13, 27, 28, 29, 15, 31, 32, 33, 17, 7, 36, 37, 19, 39, 40, 41, 21, 43, 44, 9, 23, 47, 48, 49, 25, 51, 4, 53, 27, 55, 56, 57, 29, 59, 12, 61, 31, 63, 64, 65, 33, 67, 68, 69, 7, 71, 72, 73, 37, 75, 76
Offset: 0

Views

Author

Wolfdieter Lang, Jan 21 2008

Keywords

Comments

The numerators are given in A135808.

Examples

			Rationals r(n)=[0,0,1/3, 1/4, 8/5, 8/3, 159/7, 659/8, 6824/9, 4668, 517581/11,...].
		

Crossrefs

Cf. A135808 (numerators), A134832.

Formula

a(n) = denominator(r(n)) with the rationals r(n) from the given e.g.f.
E.g.f. for rationals r(n): (1-exp(x)/(1-log(1-x)))/x.
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