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.

A322197 Antidiagonal sums of square table A322190.

Original entry on oeis.org

1, 2, 3, 6, 15, 46, 168, 710, 3405, 18270, 108438, 705334, 4989075, 38126414, 313034088, 2748039078, 25685633625, 254672239678, 2669718010218, 29502715813142, 342784073066655, 4177349457737262, 53279132429530428, 709785147883342726, 9858698782067445765, 142530638751865262366, 2141519206261256136318, 33391802751245681847030, 539616796036523449056555, 9026558167976152019922190
Offset: 0

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Author

Paul D. Hanna, Dec 20 2018

Keywords

Comments

Table A322190 gives the coefficients of x^n*y^k/(n!*k!) in (cosh(x)*cosh(y) + sinh(x) + sinh(y)) / (1 - sinh(x)*sinh(y)).

Crossrefs

Cf. A244920.

Programs

  • Mathematica
    nmax = 30;
    t[n_, k_] := SeriesCoefficient[(Cosh[x] Cosh[y] + Sinh[x] + Sinh[y])/(1 - Sinh[x] Sinh[y]), {x, 0, n}, {y, 0, k}] n! k!;
    a[n_] := Sum[t[n - k, k], {k, 0, n}];
    Table[a[n], {n, 0, nmax}] (* Jean-François Alcover, Dec 29 2018 *)

Formula

a(n) ~ Pi * n^(n+1) / (2^(n - 3/4) * exp(n) * (log(1+sqrt(2)))^(n + 3/2)). - Vaclav Kotesovec, Dec 30 2018