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URL: https://oeis.org/A326985

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A326985
G.f.: B(x)*B(2*x^2)*B(3*x^3)*..., where B(x) is g.f. of A000312.
4
1, 1, 6, 32, 287, 3222, 47606, 831488, 16890792, 389286222, 10037183606, 286154919078, 8937624574652, 303483905672078, 11130904101218094, 438532313635906858, 18470060947222927499, 828155619735377936654, 39384843256547964375436, 1980138439071577626157382
OFFSET
0,3
LINKS
FORMULA
a(n) ~ n^n.
MAPLE
B:= proc(n) option remember; n^n end:
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i=1,
B(n), add(b(j, 1)*i^j*b(n-i*j, i-1), j=0..n/i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..20); # Alois P. Heinz, Aug 23 2019
MATHEMATICA
nmax = 20; CoefficientList[Series[Product[1+Sum[k^k*j^k*x^(j*k), {k, 1, nmax/j}], {j, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Aug 10 2019
STATUS
approved