A091346 Binomial convolution of A069321(n), where A069321(0)=0, with the sequence of all 1's alternating in sign.
0, 1, 3, 19, 135, 1171, 11823, 136459, 1771815, 25561891, 405658143, 7022891899, 131714587095, 2660335742611, 57570797744463, 1328913670495339, 32592691757283975, 846383665814211331, 23200396829832102783, 669421949061096050779, 20281206249626018470455
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
Crossrefs
Cf. A083410.
Programs
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Maple
b:= proc(n, k) option remember; `if`(n=0, k!, k*b(n-1, k)+b(n-1, k+1)) end: a:= n-> (b(n+1, 0)-(-1)^n)/4: seq(a(n), n=0..23); # Alois P. Heinz, Feb 14 2025
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Mathematica
Table[Sum[Binomial[n, k](-1)^(n-k)Sum[i!i StirlingS2[k, i], {i, 1, k}], {k, 0, n}], {n, 0, 20}] Table[(-1)^n LerchPhi[2, -n-1, 2]/2, {n, 0, 20}] (* Federico Provvedi, Sep 04 2020 *) a[n_] := (-1)^n (PolyLog[-1 - n, 2] - 2) / 8; Table[a[n], {n, 0, 20}] (* Peter Luschny, Nov 09 2020 *) a[n_] := (-1)^n HurwitzLerchPhi[2, -n-1, 2] / 2; Table[a[n], {n, 0, 20}] (* Federico Provvedi, Nov 11 2020 *)
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PARI
a(n) = sum(k=0, n, binomial(n, k)*(-1)^(n-k)*sum(i=1, k, i!*i*stirling(k, i, 2))); \\ Michel Marcus, Jun 25 2019
Formula
a(n) = Sum_{k=0..n}(C(n, k)*(-1)^(n-k)*Sum_{i=1..k}(i!*i*Stirling2(k, i))).
E.g.f.: ((exp(x)-1)/(2-exp(x))^2)*exp(-x).
a(n) = (A000670(n+1)+(-1)^(n+1))/4. - Vladeta Jovovic, Jan 17 2005
G.f.: x/(1+x)/Q(0), where Q(k) = 1 - x*(3*k+4) - 2*x^2*(k+1)*(k+3)/Q(k+1); (continued fraction). - Sergei N. Gladkovskii, Oct 03 2013
a(n) ~ n! * n / (8 * (log(2))^(n+2)). - Vaclav Kotesovec, Nov 27 2017
a(n) = (1/2) * (-1)^n * Phi(2, -n-1, 2), where Phi(z, s, a) is the Lerch transcendantal function. - Federico Provvedi, Sep 04 2020
a(n ) = (-1)^n * (PolyLog(-1 - n, 2) - 2) / 8. - Peter Luschny, Nov 09 2020
Comments