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A189487 E.g.f. exp(x*exp(x)+x^2*exp(2*x)) 0
1, 1, 5, 28, 185, 1456, 13267, 135598, 1528193, 18805240, 250522451, 3585332554, 54774501025, 888739031116, 15249006695483, 275641537989766, 5231788966650113, 103968303762747472, 2157673505603964643, 46656574558459795522, 1049037051211541521121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..20.

Vladimir Kruchinin, D. V. Kruchinin, Composita and their properties, arXiv:1103.2582

FORMULA

a(n)=n!*sum(m=1..n, sum(k=m..n, (k^(n-k)*binomial(m,k-m))/(n-k)!)/m!), n>0, a(0)=1.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Exp[x Exp[x]+x^2 Exp[2x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Sep 22 2011 *)

PROG

(Maxima)

a(n):=n!*sum(sum((k^(n-k)*binomial(m, k-m))/(n-k)!, k, m, n)/m!, m, 1, n);

CROSSREFS

Sequence in context: A331797 A123776 A070779 * A024065 A003467 A240770

Adjacent sequences:  A189484 A189485 A189486 * A189488 A189489 A189490

KEYWORD

nonn

AUTHOR

Vladimir Kruchinin, Apr 23 2011

EXTENSIONS

More terms from Harvey P. Dale, Sep 22 2011

STATUS

approved

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Last modified August 7 04:39 EDT 2020. Contains 336274 sequences. (Running on oeis4.)