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A108176
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a(1) = 1, a(n) = (Sum_{k=1..floor(n/2)} 1/a(n + 1 - 2k))*(Product_{k=1..floor(n/2)} a(n + 1 - 2k)).
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1
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1, 1, 1, 2, 3, 7, 23, 164, 3786, 620973, 2351006074, 1459911295051236, 3432260322166663402961472, 5010795611887306064313121202903094714708, 17198354961167628388233455836547370709483687001035342768448084064
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OFFSET
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1,4
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LINKS
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FORMULA
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For n >= 2, a(n+4) = a(n+1)*(a(n+2) - a(n)a(n+1)) + a(n+2)a(n+3).
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MAPLE
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a[1]:=1: for n from 2 to 25 do a[n]:=sum(1/a[n+1-2*j], j=1..floor(n/2))*product(a[n+1-2*k], k=1..floor(n/2)) od: seq(a[n], n=1..16); # Emeric Deutsch, Jun 14 2005
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Sum[1/a[n + 1 - 2k], {k, Floor[n/2]}] Product[ a[n + 1 - 2k], {k, Floor[n/2]}]; Table[ a[n], {n, 15}] (* Robert G. Wilson v, Jun 14 2005 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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