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A355101
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E.g.f. A(x) satisfies A(x) = 1 + 3 * x * A(exp(x) - 1).
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2
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1, 3, 18, 189, 2952, 63225, 1759374, 61261200, 2595618720, 130963993263, 7734817065600, 527276606418837, 41005535326851456, 3602215645092352314, 354438336568129922052, 38776184401330464272910, 4686507224871009709115232, 622194587177907979874119473
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OFFSET
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0,2
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LINKS
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FORMULA
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a(0) = 1; a(n) = 3 * n * Sum_{k=0..n-1} Stirling2(n-1,k) * a(k).
a(n) = 3 * n * A355092(n-1) for n>0.
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PROG
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(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=3*i*sum(j=0, i-1, stirling(i-1, j, 2)*v[j+1])); v;
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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