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A174483 a(n) = coefficient of x^n/(n-1)! in the (n+1)-th iteration of x*exp(x) for n>=1. 5
1, 3, 28, 575, 21216, 1242892, 106459312, 12577403841, 1962856001440, 391431498879806, 97160350830990624, 29387077319612739025, 10642369538735639329912, 4547196797035053394680280 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

The initial n-th iterations of x*exp(x) begin:

n=1: x + x^2 + x^3/2! + x^4/3! + x^5/4! + x^6/5! +...

n=2: (1)*x +2*x^2 + 6*x^3/2! + 23*x^4/3! + 104*x^5/4! + 537*x^6/5! +...

n=3: x +(3)*x^2 +15*x^3/2! +102*x^4/3! +861*x^5/4! +8598*x^6/5! +...

n=4: x + 4*x^2 +(28)*x^3/2! +274*x^4/3! +3400*x^5/4! +50734*x^6/5! +...

n=5: x + 5*x^2 +45*x^3/2! +(575)*x^4/3! +9425*x^5/4! +187455*x^6/5! +...

n=6: x + 6*x^2 +66*x^3/2! +1041*x^4/3! +(21216)*x^5/4!+527631*x^6/5!+...

n=7: x + 7*x^2 +91*x^3/2! +1708*x^4/3! +41629*x^5/4! +(1242892)*x^6/5! +...

This sequence starts with the above coefficients in parenthesis.

PROG

(PARI) {a(n)=local(E=x*exp(x+x*O(x^n)), F=x); for(i=1, n+1, F=subst(F, x, E)); (n-1)!*polcoeff(F, n)}

CROSSREFS

Cf. A174480, A174481, A174482, A174484.

Sequence in context: A248571 A062497 A056066 * A092985 A181588 A084880

Adjacent sequences:  A174480 A174481 A174482 * A174484 A174485 A174486

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Apr 09 2010

STATUS

approved

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Last modified June 19 19:11 EDT 2019. Contains 324222 sequences. (Running on oeis4.)