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A351941
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a(0) = 1; a(n) = -Sum_{k=0..floor((n-1)/2)} binomial(n-1,2*k) * a(k) * a(n-2*k-1).
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0
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1, -1, 1, 0, -3, 8, -3, -57, 225, -96, -2991, 13873, -255, -313506, 1495089, 1473024, -54621231, 243365688, 705129201, -14109279483, 53228648865, 349791931434, -5000315242479, 13572033641204, 204954070915977, -2294997521498172, 2691551249257017
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OFFSET
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0,5
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LINKS
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FORMULA
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E.g.f.: exp( -Sum_{n>=0} a(n) * x^(2*n+1) / (2*n+1)! ).
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MATHEMATICA
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a[0] = 1; a[n_] := a[n] = -Sum[Binomial[n - 1, 2 k] a[k] a[n - 2 k - 1], {k, 0, Floor[(n - 1)/2]}]; Table[a[n], {n, 0, 26}]
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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