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.

A298373 a(n) = n! * [x^n] exp(n*x - exp(x) + 1).

Original entry on oeis.org

1, 0, 0, 1, 17, 273, 4779, 93532, 2047730, 49854795, 1339872113, 39462731031, 1265248227869, 43895994373580, 1639148060192408, 65568985769784897, 2797922570156143597, 126880981472647625557, 6094210606862471240855, 309087628703330034215088, 16508178701980033054460042
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 18 2018

Keywords

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Rationals(), 50);
    A298373:= func< n | Coefficient(R!(Laplace( Exp(-Exp(x)+n*x+1) )), n) >;
    [A298373(n): n in [0..30]]; // G. C. Greubel, Jun 12 2024
    
  • Maple
    b:= proc(n, k) option remember; `if`(n=0, 1,
          k*b(n-1, k)+ b(n-1, k-1))
        end:
    a:= n-> abs(b(n, -n)):
    seq(a(n), n=0..20);  # Alois P. Heinz, Aug 04 2021
  • Mathematica
    Table[n! SeriesCoefficient[Exp[n x - Exp[x] + 1], {x,0,n}], {n,0,20}]
    Join[{1}, Table[Sum[Binomial[n, k] n^(n-k) BellB[k,-1] , {k,0,n}], {n,20}]]
  • SageMath
    [factorial(n)*( exp(-exp(x) +n*x+1) ).series(x, n+1).list()[n] for n in (0..30)] # G. C. Greubel, Jun 12 2024

Formula

a(n) = Sum_{k=0..n} binomial(n,k)*n^(n-k)*A000587(k).
a(n) ~ exp(1-exp(1)) * n^n. - Vaclav Kotesovec, Aug 04 2021