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Search: id:A124381
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| A124381 |
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O.g.f.: A(x) = Sum_{n>=0} x^n*Product_{k=0..n} (1 + k*(k+1)/2*x). |
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+0
1
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| 1, 1, 2, 5, 14, 48, 181, 772, 3620, 18511, 102869, 613584, 3926895, 26734671, 193310243, 1477081245, 11896869336, 100700815331, 893438783126, 8291513009130, 80302486087937, 810290260679230, 8502192961792190
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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A(x) = 1 + x*(1+x) + x^2*(1+x)*(1+3x) + x^3*(1+x)*(1+3x)*(1+6x) +...
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PROGRAM
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(PARI) a(n)=polcoeff(sum(k=0, n, x^k*prod(j=0, k, 1+j*(j+1)/2*x+x*O(x^n))), n)
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CROSSREFS
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Adjacent sequences: A124378 A124379 A124380 this_sequence A124382 A124383 A124384
Sequence in context: A119841 A129778 A060797 this_sequence A131236 A119499 A079452
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Oct 28 2006
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