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.

A119490 Sum of the absolute values in row n of A118687.

Original entry on oeis.org

1, 2, 4, 8, 16, 80, 400, 10000, 250000, 48250000, 83424250000, 1441654464250000, 24913230796704250000, 5166032451235389984250000, 1071233655120621702524064250000, 3109835221395024747917162004384250000, 135419643726614411057926317695276801184250000
Offset: 0

Views

Author

Roger L. Bagula, May 25 2006

Keywords

Crossrefs

Cf. A118687.

Programs

  • Mathematica
    A049614[n_]:= n!/Product[Prime[i], {i, 1, PrimePi[n]}];
    b:= Join[{{1}}, Table[CoefficientList[Product[1 -A049614[k]*x, {k,0,n}], x], {n, 0, 21}]];
    Table[Sum[Abs[b[[n, j]]], {j, n}], {n, 20}] (* G. C. Greubel, Feb 07 2021 *)
  • Sage
    def A049614(n): return factorial(n)/product( nth_prime(j) for j in (1..prime_pi(n)) )
    def A118687(n,k): return ( product(1 -A049614(k)*x for k in (0..n)) ).series(x, n+2).list()[k]
    [1]+[sum(abs(A118687(n, k)) for k in (0..n+1)) for n in (0..20)] # G. C. Greubel, Feb 07 2021

Extensions

Terms a(12) onward added by G. C. Greubel, Feb 07 2021