login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A088695 E.g.f: A(x) = f(x*A(x)), where f(x) = exp(x+x^2). 0
1, 1, 5, 40, 485, 7776, 156457, 3788800, 107414505, 3491200000, 128019454541, 5229222395904, 235490648957005, 11592449531084800, 619331166211640625, 35691050995648823296, 2206955604752999720273, 145757527499874820423680, 10240455593560436925898645 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Radius of convergence of A(x): r = (1/2)*exp(-3/4) = 0.23618..., where A(r) = exp(3/4) and r = limit a(n)/a(n+1)*(n+1) as n->infinity. Radius of convergence is from a general formula yet unproved.

LINKS

Table of n, a(n) for n=0..18.

FORMULA

a(n) = n! * [x^n] exp(x+x^2)^(n+1)/(n+1).

a(n) = n!*sum(k=floor(n/2)..n, binomial(k,n-k)*(n+1)^(k-1)/k!). - Vladimir Kruchinin, Aug 04 2011

a(n) ~ 2^(n+1/2) * n^(n-1) / (sqrt(3) * exp(n/4 - 3/4)). - Vaclav Kotesovec, Jan 24 2014

MATHEMATICA

Table[n!*SeriesCoefficient[(E^(x+x^2))^(n+1)/(n+1), {x, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Jan 24 2014 *)

PROG

(PARI) a(n)=n!*polcoeff(exp(x+x^2)^(n+1)+x*O(x^n), n, x)/(n+1)

CROSSREFS

Sequence in context: A281160 A282476 A198247 * A145166 A113079 A211046

Adjacent sequences:  A088692 A088693 A088694 * A088696 A088697 A088698

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Oct 07 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 17:58 EST 2020. Contains 331296 sequences. (Running on oeis4.)