A210028 E.g.f. A(x) satisfies: A(x) = 1 / [Sum_{n>=0} (-x)^n*A(x)^n/n!^2], where A(x) = Sum_{n>=0} a(n)*x^n/n!^2.

1, 1, 7, 136, 5243, 337926, 32835687, 4489157296, 821988647139, 194271151505410, 57588227767731323, 20926176288185481600, 9148417925040487304917, 4737353391259130086721836, 2867750643606307859579827455, 2006632021748934960936683256384

Offset

0,3

Links

Table of n, a(n) for n=0..15.

Example

E.g.f.: A(x) = 1 + x + 7*x^2/2!^2 + 136*x^3/3!^2 + 5243*x^4/4!^2 + 337926*x^5/5!^2 +...
such that
A(x) = 1/(1 - x*A(x) + x^2*A(x)^2/2!^2 - x^3*A(x)^3/3!^2 + x^4*A(x)^4/4!^2  +...).

Prog

(PARI) {a(n)=n!^2*polcoeff(1/x*serreverse(x*sum(m=0, n, (-x)^m/m!^2)+x^2*O(x^n)), n)}
for(n=0, 31, print1(a(n), ", "))

Crossrefs

Sequence in context: A081793 A296595 A368630 * A243684 A260535 A220380

Adjacent sequences: A210025 A210026 A210027 * A210029 A210030 A210031

Keyword

nonn

Author

Paul D. Hanna, Mar 16 2012

Status

approved