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A186633
G.f.: Product_{n>=1} (1 + n^n*x^n)^(1/n).
5
1, 1, 2, 11, 71, 705, 8470, 127284, 2231342, 45505041, 1048341387, 27059612615, 771505041184, 24109351520196, 818862556900962, 30044548635160841, 1184027932446520895, 49883835880381353808, 2237276988838875420087
OFFSET
0,3
LINKS
FORMULA
a(n) ~ n^(n-1). - Vaclav Kotesovec, Nov 06 2014
EXAMPLE
G.f.: A(x) = 1 + x + 2*x^2 + 11*x^3 + 71*x^4 + 705*x^5 +...
A(x) = (1 + x) *(1 + 4*x^2)^(1/2) *(1 + 27*x^3)^(1/3) *(1 + 256*x^4)^(1/4) *...
PROG
(PARI) {a(n)=if(n<0, 0, polcoeff(prod(k=1, n, (1+k^k*x^k+x*O(x^n))^(1/k)), n))}
CROSSREFS
Cf. variant: A023881.
Sequence in context: A334048 A047776 A214692 * A291301 A154887 A371518
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 19 2011
STATUS
approved