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.

A283719 Main diagonal of A283674.

Original entry on oeis.org

1, 1, 17, 19748, 4295531890, 298024338096736401, 10314425731041362057808006400, 256923578002337121862310634348534055243302, 6277101735598269851830651637045695165917698976435202316054
Offset: 0

Views

Author

Seiichi Manyama, Mar 15 2017

Keywords

Crossrefs

Cf. A283674.

Programs

  • Mathematica
    nmax = 20; Table[SeriesCoefficient[Product[1/(1 - x^k)^(k^(n*k)), {k, 1, nmax}], {x, 0, n}], {n, 0, nmax}] (* Vaclav Kotesovec, Mar 17 2017 *)
  • Ruby
    def s(k, i)
      s = 0
      (1..i).each{|j| s += j ** (k * j + 1) if i % j == 0}
      s
    end
    def A(k, n)
      ary = [1]
      s_ary = [0] + (1..n).map{|i| s(k, i)}
      (1..n).each{|i| ary << (1..i).inject(0){|s, j| s + ary[-j] * s_ary[j]} / i}
      ary
    end
    def A283719(n)
      (0..n).map{|i| A(i, i)[-1]}
    end

Formula

a(n) ~ n^(n^2) * (1 + 1/(exp(n-1/2)*n^n)). - Vaclav Kotesovec, Mar 17 2017