A228852 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k*(n-k))/2 ).

1, 1, 2, 14, 382, 38344, 12990279, 14369538529, 50897796053428, 572602411324905786, 20308462423438736818782, 2261760763404526386241849803, 788248543938180828988762846368690, 857323841081698966408121705146996762240, 2905542652088907570108828021890682181041282730

Offset

0,3

Comments

Self-convolution yields A207135.

Links

Table of n, a(n) for n=0..14.

Example

G.f.: A(x) = 1 + x + 2*x^2 + 14*x^3 + 382*x^4 + 38344*x^5 + 12990279*x^6 +...
where
log(A(x)) = x + 3*x^2/2 + 37*x^3/3 + 1471*x^4/4 + 189751*x^5/5 + 77708973*x^6/6 +...+ A207136(n)/2 * x^n/n +...

Prog

(PARI) {a(n)=polcoeff(exp(sum(m=1, n, x^m/m*sum(k=0, m, binomial(m^2, k*(m-k))/2))+x*O(x^n)), n)}
for(n=0, 20, print1(a(n), ", "))

Crossrefs

Cf. A207135, A207136.

Sequence in context: A255493 A013039 A011809 * A242876 A102596 A354465

Adjacent sequences: A228849 A228850 A228851 * A228853 A228854 A228855

Keyword

nonn

Author

Paul D. Hanna, Sep 05 2013

Status

approved