A205804 E.g.f.: -log( Sum_{n>=0} (-x)^(n^2) / (n^2)! ).

1, 1, 2, 5, 19, 90, 510, 3395, 25831, 221140, 2104310, 22027170, 251540795, 3111928820, 41460769350, 591847005749, 9011786683883, 145794610986004, 2497443795363566, 45157627509568965, 859494143391347310, 17176870199851102510, 359623890969235361700

Offset

1,3

Links

Table of n, a(n) for n=1..23.

Example

E.g.f.: A(x) = x + x^2/2! + 2*x^3/3! + 5*x^4/4! + 19*x^5/5! + 90*x^6/6! +...
where
exp(-A(x)) = 1 - x + x^4/4! - x^9/9! + x^16/16! - x^25/25! + x^36/36! +...

Prog

(PARI) {a(n) = n!*polcoeff(-log(sum(m=0, sqrtint(n+1), (-x)^(m^2)/(m^2)!+x*O(x^n))), n)}
for(n=1, 25, print1(a(n), ", "))

Crossrefs

Cf. A205802, A205803.

Sequence in context: A124348 A323389 A268605 * A052324 A020115 A103816

Adjacent sequences: A205801 A205802 A205803 * A205805 A205806 A205807

Keyword

nonn

Author

Paul D. Hanna, Jan 31 2012

Status

approved