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A355986
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a(n) = Sum_{k=1..n} floor(n/k)!.
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0
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1, 3, 8, 28, 125, 731, 5052, 40352, 362917, 3628935, 39916936, 479002360, 6227021561, 87178296283, 1307674373184, 20922789928484, 355687428136485, 6402373706091651, 121645100409195652, 2432902008180269688, 51090942171713074013, 1124000727777647602015
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(6) = 6! + 3! + 2! + 1! + 1! + 1! = 731.
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MATHEMATICA
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a[n_] := Sum[Floor[n/k]!, {k, 1, n}]; Array[a, 22] (* Amiram Eldar, Jul 22 2022 *)
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PROG
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(PARI) a(n) = sum(k=1, n, (n\k)!);
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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