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A167006
G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, n*k) ).
13
1, 2, 6, 66, 4258, 1337374, 1933082159, 11353941470188, 291885138650054688, 29463501750534915665304, 12844314786465829040693498639, 21675661852919288704454219459892060, 156969579902607123047763327413679853875703
OFFSET
0,2
COMMENTS
Logarithmic derivative yields A167009.
Equals row sums of triangle A209196.
LINKS
EXAMPLE
G.f.: A(x) = 1 + 2*x + 6*x^2 + 66*x^3 + 4258*x^4 + 1337374*x^5 +...
log(A(x)) = 2*x + 8*x^2/2 + 170*x^3/3 + 16512*x^4/4 + 6643782*x^5/5 + 11582386286*x^6/6 +...+ A167009(n)*x^n/n +...
PROG
(PARI) {a(n)=polcoeff(exp(sum(m=1, n, sum(k=0, m, binomial(m^2, k*m))*x^m/m)+x*O(x^n)), n)}
for(n=0, 20, print1(a(n), ", "))
CROSSREFS
Cf. variants: A206848, A228809.
Sequence in context: A217630 A091458 A335934 * A087331 A097419 A219037
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 17 2009
STATUS
approved