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.

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

A059604 Coefficients of polynomials (n-1)!*P(n,k), P(n,k) = Sum_{i=0..n} Stirling2(n,i)*binomial(k+i-1,k).

Original entry on oeis.org

1, 1, 2, 1, 9, 10, 1, 24, 107, 90, 1, 50, 575, 1750, 1248, 1, 90, 2135, 16050, 38244, 24360, 1, 147, 6265, 95445, 537334, 1078728, 631440, 1, 224, 15610, 424340, 4734289, 21569996, 38105220, 20865600, 1, 324, 34482, 1529640, 30128049
Offset: 1

Views

Author

Vladeta Jovovic, Jan 29 2001

Keywords

Examples

			[1],
[1, 2],
[1, 9, 10],
[1, 24, 107, 90],
[1, 50, 575, 1750, 1248],
[1, 90, 2135, 16050, 38244, 24360],
[1, 147, 6265, 95445, 537334, 1078728, 631440],
...
P(2,k) = k + 2,
P(3,k) = (1/2!)*(k^2 + 9*k + 10),
P(4,k) = (1/3!)*(k^3 + 24*k^2 + 107*k + 90).
		

Crossrefs

Programs

  • Maple
    P := (n, k) -> (n-1)!*add(Stirling2(n,i)*binomial(k+i-1,k), i=0..n):
    for n from 1 to 8 do seq(coeff(expand(P(n,x)),x,n-k), k=1..n) od; # Peter Luschny, Nov 07 2018
  • Mathematica
    row[n_] := (n-1)! CoefficientList[Sum[StirlingS2[n,i] Binomial[k+i-1,k] // FunctionExpand, {i,0,n}], k] // Reverse;
    Array[row,10] // Flatten (* Jean-François Alcover, Jun 03 2019 *)
  • PARI
    row(n)={Vec((n-1)!*sum(i=0, n, stirling(n,i,2)*binomial(x+i-1,i-1)))}
    for(n=1, 10, print(row(n))) \\ Andrew Howroyd, Nov 07 2018
Showing 1-2 of 2 results.