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 A187656 Convolution of the (signless) central Stirling numbers of the first kind (A187646). 0
 1, 2, 23, 472, 14109, 557138, 27417263, 1617536576, 111304630793, 8752522524930, 774271257457719, 76102169738598232, 8227653697751043061, 970337814111625277394, 123968202132756025685151, 17055359730313188973301568 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n) = sum(s(2k,k)s(2n-2k,n-k)),k=0..n) MAPLE seq(sum(abs(combinat[stirling1](2*k, k))*abs(combinat[stirling1](2*(n-k), n-k)), k=0..n), n=0..12); MATHEMATICA Table[Sum[Abs[StirlingS1[2k, k]]Abs[StirlingS1[2n - 2k, n - k]], {k, 0, n}], {n, 0, 15}] PROG (Maxima) makelist(sum(abs(stirling1(2*k, k))*abs(stirling1(2*n-2*k, n-k)), k, 0, n), n, 0, 12); CROSSREFS Cf. A187646 Sequence in context: A119774 A074649 A134355 * A054260 A053160 A167416 Adjacent sequences:  A187653 A187654 A187655 * A187657 A187658 A187659 KEYWORD nonn,easy AUTHOR Emanuele Munarini, Mar 12 2011 STATUS approved

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