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.

A002681 Numerators of coefficients for repeated integration.

Original entry on oeis.org

1, -1, 1, -23, 263, -133787, 157009, -16215071, 2689453969, -26893118531, 5600751928169, -3340626516019229, 885646796787371, -859202038021848149, 2766671664340938282413, -319473088311274492668499, 436677987276721765221113, -191960665849028069896950959123
Offset: 0

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References

  • 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

Programs

  • Maple
    M:=n->(2/(2*n+1)!)*int(t*product(t^2-k^2,k=1..n),t=0..1): A:=n->((n+1)/2)*M(n)+(2*n+2)*M(n+1): seq(numer(A(n)),n=0..18); # Emeric Deutsch, Jan 25 2005
  • Mathematica
    M[n_] := (2/(2n+1)!) Integrate[t Product[t^2-k^2, {k, 1, n}], {t, 0, 1}];
    A[n_] := ((n+1)/2) M[n] + (2n+2) M[n+1];
    Table[Numerator[A[n]], {n, 0, 18}] (* Jean-François Alcover, Oct 04 2021, after Maple code *)

Formula

a(n) is the numerator of ((n+1)/2)M(n) + (2n+2)M(n+1), where M(n) = (2/(2n+1)!)*Integral_{t=0..1} (t*Product_{k=1..n} (t^2 - k^2)). - Emeric Deutsch, Jan 25 2005

Extensions

More terms from Emeric Deutsch, Jan 25 2005