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A126656
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a(1)=1; for n>1, a(n) = Sum_{k=1..n-1} a(k) * floor(n/k).
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9
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1, 2, 5, 13, 27, 62, 125, 266, 538, 1106, 2213, 4509, 9019, 18166, 36365, 73012, 146025, 292658, 585317, 1171783, 2343697, 4689610, 9379221, 18763300, 37526628, 75062278, 150125100, 300268507, 600537015, 1201111598, 2402223197
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) is asymptotic to c*2^n where c=1.1186567921399193608303756752855835542518061417771006467002421299046146... [Benoit Cloitre, Nov 10 2009]
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MAPLE
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for n from 2 to 100 do
od:
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MATHEMATICA
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f[l_List] := Block[{n = Length[l] + 1}, Append[l, Sum[l[[k]]*Floor[n/k], {k, n - 1}]]]; Nest[f, {1}, 32] (* Ray Chandler, Feb 11 2007 *)
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PROG
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(Magma) sol:=[1]; for n in [2..31] do Append(~sol, &+[sol[k]*Floor(n/k):k in [1..n-1]]); end for; sol; // Marius A. Burtea, Sep 07 2019
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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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