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 1-3 of 3 results.

A122778 a(n) = Sum_{k=0..n} A(n,k)*n^k where A(n,k) are Eulerian numbers.

Original entry on oeis.org

1, 1, 3, 22, 285, 5656, 158095, 5881968, 279768825, 16507789696, 1180490926131, 100415158796800, 10005244013129365, 1152844128057793536, 151949197139815794615, 22696027820066041133056, 3810644613584486281328625
Offset: 0

Views

Author

Max Alekseyev, Sep 11 2006

Keywords

Comments

Prime p divides a(p-1) for p>2. - Alexander Adamchuk, Sep 12 2006
Let A_n(x) denote the Eulerian polynomials with coefficients the Eulerian numbers as defined in the DLMF (number of permutations of {1,2,..,n} with k ascents) then a(n) = A_n(n). - Peter Luschny, Aug 09 2010

Crossrefs

Cf. A008292.

Programs

  • Maple
    A122778 := n -> add(n^k*add((-1)^j*binomial(n+1,j)*(k-j+1)^n,j=0..k),k=0..n); # Peter Luschny, Aug 09 2010
    seq(add(combinat:-eulerian1(n,k)*n^k,k=0..n),n=0..16); # Peter Luschny, Oct 19 2016
  • Mathematica
    << Combinatorica`; Table[Sum[Combinatorica`Eulerian[n, k] If[n == k == 0, 1, n^k], {k, 0, n}], {n, 0, 20}] (* Alexander Adamchuk, Sep 12 2006; corrected by Vladimir Reshetnikov, Oct 15 2016 *)
    Flatten[{1, 1, Table[(n-1)^(n+1)*PolyLog[-n, 1/n]/n, {n, 2, 20}]}] (* Vaclav Kotesovec, Oct 16 2016 *)

Formula

a(n) = Sum_{k=0..n} A(n,k) * n^k
a(n) = Sum_{k=0..n} A(n,k) * n^(n-k).
a(n) = ((n-1)^(n+1))/n * Sum_{k>=1} k^n/n^k for n>1.
a(n) = ((n-1)^(n+1))/n * Li_{-n}(1/n) for n>1. - Alexander Adamchuk, Sep 12 2006
a(n) = (n-1)*A086914(n), n>1. - Vladeta Jovovic, Sep 12 2006
a(n) ~ exp(-1) * n! * n^n / log(n)^(n+1). - Vaclav Kotesovec, Jun 06 2022

Extensions

a(0)=1 changed by Max Alekseyev, Nov 28 2011

A331690 a(n) = Sum_{k=0..n} Stirling2(n,k) * k! * n^(n - k).

Original entry on oeis.org

1, 1, 4, 33, 456, 9445, 272448, 10386817, 503758720, 30202999821, 2189000524800, 188349613075393, 18954958449853440, 2203304642871358741, 292675996808408743936, 44022321302156791898625, 7438113993194856900034560, 1401876939543892434209075581
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 24 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Join[{1}, Table[Sum[StirlingS2[n, k] k! n^(n - k), {k, 0, n}], {n, 1, 17}]]
    Table[SeriesCoefficient[Sum[k! x^k/Product[(1 - n j x), {j, 1, k}], {k, 0, n}], {x, 0, n}], {n, 0, 17}]
    Join[{1}, Table[n^(n + 1) PolyLog[-n, 1/(n + 1)]/(n + 1), {n, 1, 17}]]
  • PARI
    a(n) = sum(k=0, n, stirling(n, k, 2)*k!*n^(n-k)); \\ Michel Marcus, Jan 24 2020

Formula

a(n) = [x^n] Sum_{k>=0} k! * x^k / Product_{j=1..k} (1 - n*j*x).
a(n) = n! * [x^n] n / (1 + n - exp(n*x)) for n > 0.
a(n) = n^(n + 1) * Sum_{k>=1} k^n / (n + 1)^(k + 1) for n > 0.
a(n) ~ n! * n^(n+1) / ((n+1) * log(n+1)^(n+1)). - Vaclav Kotesovec, Jun 06 2022

A122020 Sum[k=0..n] Eulerian[n,k]*n^k.

Original entry on oeis.org

1, 6, 66, 1140, 28280, 948570, 41173776, 2238150600, 148570107264, 11804909261310, 1104566746764800, 120062928157552380, 14986973664751315968, 2127288759957421124610, 340440417300990616995840
Offset: 1

Views

Author

Alexander Adamchuk, Sep 12 2006, Sep 14 2006

Keywords

Comments

n divides a(n). 2^m divides a(n), where m(n) = {0,1,1,2,3,1,4,3,7,1,9,2,10,1,11,4,15,1,17,2,18,1,20,3,22,...}. p^k divides from a(p^k-1), a(p^k), a(p^k+1) for prime p>2 and integer k>0.

Crossrefs

Programs

  • Mathematica
    Table[Sum[Eulerian[n,k]*n^k,{k,0,n}],{n,1,25}]
    Flatten[{1, Table[(n-1)^(n+1)*PolyLog[-n, 1/n], {n, 2, 20}]}] (* Vaclav Kotesovec, Oct 16 2016 *)

Formula

a(n) = Sum[ Eulerian[n,k]*n^(n-k-1), {k,0,n} ] = n*A122778[n]. a(n) = n(n-1)*A086914[n] for n>1. a(n) = ((n-1)^(n+1)) * PolyLog[ -n, 1/n ] = ((n-1)^(n+1)) * Sum[ k^n/n^k, {k,1,Infinity} ] = ((n-1)^(n+1)) * A121376[n]/A121985[n] for n>1.
a(n) ~ exp(-1) * n! * n^(n+1) / log(n)^(n+1). - Vaclav Kotesovec, Jun 06 2022
Showing 1-3 of 3 results.