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.

Showing 1-2 of 2 results.

A059605 a(n) = (1/3!)*(n^3 + 24*n^2 + 107*n + 90), compare A059604.

Original entry on oeis.org

15, 37, 68, 109, 161, 225, 302, 393, 499, 621, 760, 917, 1093, 1289, 1506, 1745, 2007, 2293, 2604, 2941, 3305, 3697, 4118, 4569, 5051, 5565, 6112, 6693, 7309, 7961, 8650, 9377, 10143, 10949, 11796, 12685, 13617, 14593, 15614, 16681, 17795, 18957
Offset: 0

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Author

Vladeta Jovovic, Jan 29 2001

Keywords

Crossrefs

Programs

  • Magma
    [(1/6)*(n^3+24*n^2+107*n+90) : n in [0..50]]; // Vincenzo Librandi, Nov 13 2011

Formula

G.f.: (15 - 23*x + 10*x^2 - x^3)/(1-x)^4, compare A059340.

Extensions

More terms from James Sellers, Feb 01 2001

A059606 Expansion of (1/2)*(exp(2*x)-1)*exp(exp(x)-1).

Original entry on oeis.org

0, 1, 4, 16, 68, 311, 1530, 8065, 45344, 270724, 1709526, 11376135, 79520644, 582207393, 4453142140, 35500884556, 294365897104, 2533900264547, 22604669612078, 208656457858161, 1990060882027600
Offset: 0

Views

Author

Vladeta Jovovic, Jan 29 2001

Keywords

Comments

Starting (1, 4, 16, 68, 311, ...), = A008277 * A000217, i.e., the product of the Stirling2 triangle and triangular series. - Gary W. Adamson, Jan 31 2008

Crossrefs

Programs

  • Maple
    s := series(1/2*(exp(2*x)-1)*exp(exp(x)-1), x, 21): for i from 0 to 20 do printf(`%d,`,i!*coeff(s,x,i)) od:
  • Mathematica
    With[{nn=20},CoefficientList[Series[((Exp[2x]-1)Exp[Exp[x]-1])/2,{x,0,nn}] ,x] Range[0,nn]!] (* Harvey P. Dale, Nov 10 2011 *)

Formula

a(n) = Sum_{i=0..n} Stirling2(n, i)*binomial(i+1, 2).
a(n) = (1/2)*(Bell(n+2)-Bell(n+1)-Bell(n)). - Vladeta Jovovic, Sep 23 2003
G.f.: Sum_{k>=1} (k*(k + 1)/2)*x^k/Product_{j=1..k} (1 - j*x). - Ilya Gutkovskiy, Jun 19 2018
a(n) ~ n^2 * Bell(n) / (2*LambertW(n)^2) * (1 - LambertW(n)/n). - Vaclav Kotesovec, Jul 28 2021
Showing 1-2 of 2 results.