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.

A027647 Numerators of poly-Bernoulli numbers B_n^(k) with k=4.

Original entry on oeis.org

1, 1, -49, 41, 26291, -1921, 845233, 1048349, -60517579, -50233, 506605371959, 823605863, -53797712101337483, -7784082036337, 8049010408144441, 246319059461, -3910018782537447618421, 1090400590625849
Offset: 0

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Keywords

Crossrefs

Cf. A027648.

Programs

  • Magma
    A027647:= func< n,k | Numerator( (&+[(-1)^(j+n)*Factorial(j)*StirlingSecond(n, j)/(j+1)^k: j in [0..n]]) ) >;
    [A027647(n,4): n in [0..20]]; // G. C. Greubel, Aug 02 2022
    
  • Maple
    a:= (n, k)-> numer((-1)^n*add((-1)^m*m!*Stirling2(n, m)/(m+1)^k, m=0..n)):
    seq(a(n, 4), n = 0..30);
  • Mathematica
    With[{k = 4}, Table[Numerator@ Sum[((-1)^(m + n))*m!*StirlingS2[n, m]*(m + 1)^(-k), {m, 0, n}], {n, 0, 17}]] (* Michael De Vlieger, Mar 18 2017 *)
  • SageMath
    def A027647(n,k): return numerator( sum((-1)^(n+j)*factorial(j)*stirling_number2(n,j)/(j+1)^k for j in (0..n)) )
    [A027647(n,4) for n in (0..20)] # G. C. Greubel, Aug 02 2022

Formula

a(n) = numerator of Sum_{j=0..n} (-1)^(n+j) * j! * Stirling2(n, j) * (j+1)^(-k), for k = 4.