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.

A281231 Exponential transform of the tetrahedral numbers (A000292).

Original entry on oeis.org

1, 1, 5, 23, 133, 916, 7107, 61286, 580505, 5968400, 66032901, 780962524, 9817927385, 130572957724, 1829676460991, 26919714974436, 414591408939313, 6665930432840304, 111624874150941193, 1942675652654112012, 35071252458352443001, 655641049733709757516
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 18 2017

Keywords

Examples

			E.g.f.: A(x) = 1 + x/1! + 5*x^2/2! + 23*x^3/3! + 133*x^4/4! + 916*x^5/5! + 7107*x^6/6! + ...
		

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(a(n-j)
          *binomial(n-1, j-1)*j*(j+1)*(j+2)/6, j=1..n))
        end:
    seq(a(n), n=0..25);  # Alois P. Heinz, Jan 18 2017
  • Mathematica
    Range[0, 21]! CoefficientList[Series[Exp[Exp[x] x (1 + x + x^2/6)], {x, 0, 21}], x]

Formula

E.g.f.: exp(exp(x)*x*(1+x+x^2/6)).