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A355292
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a(n) = Sum_{k=1..n} |Stirling1(n,k)| * Catalan(k-1).
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0
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1, 2, 7, 34, 208, 1521, 12871, 123306, 1316316, 15471114, 198319614, 2751524557, 41058030388, 655427422651, 11142214939181, 200919300509214, 3829751956014084, 76928721540858772, 1624015067086462504, 35942784684670110710, 832134062464902004336
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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Table[Sum[Abs[StirlingS1[n, k]] * CatalanNumber[k-1], {k, 1, n}], {n, 1, 20}] (* Vaclav Kotesovec, Jul 01 2022 *)
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PROG
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(PARI) a(n) = sum(k=1, n, abs(stirling(n, k, 1))*binomial(2*k-2, k-1)/k);
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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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