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.

A118443 Row sums of triangle A118441, which is the matrix log of triangle A118435.

Original entry on oeis.org

1, -2, 3, -36, -155, 474, 1127, -1992, -1719, -4810, -31669, 109332, 286637, -596974, -904785, 449136, -3218287, 16156782, 50232979, -121747380, -233735691, 309853258, 15768823, 1624290984, 6853579225, -19712646746, -44873974053, 79998871428, 90434035261
Offset: 0

Views

Author

Paul D. Hanna, Apr 28 2006

Keywords

Crossrefs

Cf. A118441 (triangle), A118442 (column 0), A118444 (a(n)/(n+1)); A118435.

Programs

  • Mathematica
    nmax = 30;
    h[n_, k_] := Binomial[n, k]*(-1)^(Quotient[n+1, 2] - Quotient[k, 2]+n-k);
    H = Table[h[n, k], {n, 0, nmax}, {k, 0, nmax}];
    Cn = Table[Binomial[n, k], {n, 0, nmax}, {k, 0, nmax}];
    L = MatrixLog[H.Inverse[Cn].H];
    Total /@ Rest@L (* Jean-François Alcover, Apr 08 2024 *)
  • PARI
    {a(n)=polcoeff((1+x)*(1-3*x+18*x^2-78*x^3+45*x^4-175*x^5)/(1+6*x^2+25*x^4 +x*O(x^n))^2,n)}

Formula

G.f.: (1+x)*(1-3*x+18*x^2-78*x^3+45*x^4-175*x^5)/(1+6*x^2+25*x^4)^2.
E.g.f.: cos(2*x)*((1 - x)*cosh(x) + (1 + 3*x)*sinh(x)) - sin(2*x)*((1 + x)*cosh(x) - (1 - 3*x)*sinh(x)). - Stefano Spezia, Jul 01 2023