OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..424
FORMULA
a(n) ~ n! / (2 * (log(2))^(n+1)). - Vaclav Kotesovec, May 31 2019
MAPLE
b:= proc(n, m) option remember;
`if`(n=0, m!, m*b(n-1, m)+b(n-1, m+1))
end:
a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
b(d, 0), d=numtheory[divisors](j))*a(n-j), j=1..n)/n)
end:
seq(a(n), n=0..30);
MATHEMATICA
b[n_, m_]:=b[n, m]=If[n==0, m!, Sum[b[n - 1, Max[m, j]], {j, m + 1}]]; a[n_]:=a[n]=If[n==0, 1, Sum[Sum[d*b[d, 0], {d, Divisors[j]}] a[n - j], {j, n}]/n]; Table[a[n], {n, 0, 50}] (* Indranil Ghosh, Jul 28 2017, after Maple code *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 28 2017
STATUS
approved