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A228901
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Column 1 of triangle A228900.
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1
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1, 3, 15, 155, 2685, 65517, 2063205, 79715229, 3653521179, 193876702019, 11696128639195, 790788563411431, 59238930606369007, 4870881096635599567, 436176889680415116607, 42256722956163045301807, 4403938204071514872757477, 491317594015782152377769725, 58423874601431980415156917525
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OFFSET
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1,2
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COMMENTS
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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 ).
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LINKS
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Table of n, a(n) for n=1..19.
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PROG
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(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), ", "))
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CROSSREFS
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Cf. A228900.
Sequence in context: A162078 A245069 A317667 * A195226 A264558 A136519
Adjacent sequences: A228898 A228899 A228900 * A228902 A228903 A228904
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna, Sep 07 2013
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STATUS
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approved
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