OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..450
FORMULA
E.g.f.: Sum[k>0, -1+ exp(Sum(j>=k, x^j/j))]. - Vladeta Jovovic, Jul 26 2004
a(n) = Sum_{k=1..n} k * A145877(n,k). - Alois P. Heinz, Jul 28 2014
MAPLE
b:= proc(n, m) option remember; `if`(n=0, m, add((j-1)!*
b(n-j, min(m, j))*binomial(n-1, j-1), j=1..n))
end:
a:= n-> b(n, infinity):
seq(a(n), n=1..25); # Alois P. Heinz, May 14 2016
MATHEMATICA
Drop[Apply[Plus, Table[nn=25; Range[0, nn]!CoefficientList[Series[Exp[Sum[ x^i/i, {i, n, nn}]]-1, {x, 0, nn}], x], {n, 1, nn}]], 1] (* Geoffrey Critzer, Jan 10 2013 *)
b[n_, m_] := b[n, m] = If[n == 0, m, Sum[(j-1)! b[n-j, Min[m, j]]* Binomial[n-1, j-1], {j, n}]];
a[n_] := b[n, Infinity];
Array[a, 25] (* Jean-François Alcover, Apr 21 2020, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joe Keane (jgk(AT)jgk.org)
EXTENSIONS
More terms from Vladeta Jovovic, Sep 19 2002
STATUS
approved