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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.

A375698 Expansion of e.g.f. 1 / sqrt(1 + x^2 * log(1 - x)).

Original entry on oeis.org

1, 0, 0, 3, 6, 20, 360, 2394, 17220, 252720, 2963520, 34525260, 552027960, 8860952880, 142907532768, 2682870913800, 53297669552400, 1086135012144000, 24087251436249600, 566843973576536880, 13834256829134364000, 357412359616922433600, 9723652519748883408000
Offset: 0

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Author

Seiichi Manyama, Aug 25 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(1/sqrt(1+x^2*log(1-x))))
    
  • PARI
    a001147(n) = prod(k=0, n-1, 2*k+1);
    a(n) = n!*sum(k=0, n\3, a001147(k)*abs(stirling(n-2*k, k, 1))/(2^k*(n-2*k)!));

Formula

a(n) = n! * Sum_{k=0..floor(n/3)} A001147(k) * |Stirling1(n-2*k,k)|/(2^k*(n-2*k)!).