OFFSET
0,3
COMMENTS
Compare to: Limit_{N->oo} [ Sum_{n>=0} (N + n)^n * x^n/n! ]^(1/N) = Sum_{n>=0} (n+1)^(n-1) * x^n/n!.
EXAMPLE
E.g.f.: A(x) = 1 + x + 13*x^2/2! + 415*x^3/3! + 22321*x^4/4! + 1721101*x^5/5! + 174252997*x^6/6! + 21935478979*x^7/7! + 3308902366945*x^8/8! + 582483654850105*x^9/9! + 117302814498577501*x^10/10! +...
where A(x) equals the limit, as N -> oo, of the series
[1 + (N+3)^2*(x/N) + (N+6)^4*(x/N)^2/2! + (N+9)^6*(x/N)^3/3! + (N+12)^8*(x/N)^4/4! + (N+15)^10*(x/N)^5/5! + (N+18)^12*(x/N)^6/6! +...]^(1/N).
PROG
(PARI) /* Informal listing of terms 0..30 */
\p300
P(n) = sum(k=0, 32, (n+3*k)^(2*k) * x^k/k! +O(x^32))
Vec( round( serlaplace( subst(P(10^100)^(1/10^100), x, x/10^100) )*1.) )
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 30 2015
STATUS
approved