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.

A283720 Main diagonal of A283675.

Original entry on oeis.org

1, -1, -16, -19619, -4294403215, -298022109672568357, -10314423865939993706950978963, -256923577039780637227768848162543179896514, -6277101735175091675863380669683250419973895230549186236030
Offset: 0

Views

Author

Seiichi Manyama, Mar 15 2017

Keywords

Crossrefs

Cf. A283675.

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[(1 - x^k)^(k^(n*k)), {k, 1, 10}], {x, 0, n}], {n, 0, 10}] (* Indranil Ghosh, 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 A283720(n)
      (0..n).map{|i| A(i, i)[-1]}
    end