A228901 Column 1 of triangle A228900.

1, 3, 15, 155, 2685, 65517, 2063205, 79715229, 3653521179, 193876702019, 11696128639195, 790788563411431, 59238930606369007, 4870881096635599567, 436176889680415116607, 42256722956163045301807, 4403938204071514872757477, 491317594015782152377769725, 58423874601431980415156917525

Offset

1,2

Comments

Triangle A228900 is defined by g.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, (n-k)*k) * y^k ).

Links

Table of n, a(n) for n=1..19.

Prog

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

Crossrefs

Cf. A228900.

Sequence in context: A162078 A245069 A317667 * A195226 A264558 A136519

Adjacent sequences: A228898 A228899 A228900 * A228902 A228903 A228904

Keyword

nonn

Author

Paul D. Hanna, Sep 07 2013

Status

approved