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A275826
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Least k such that n! divides d(k!) (d = A000005, k > 0).
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1
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1, 2, 6, 8, 20, 20, 28, 36, 36, 56, 90, 90, 120, 126, 126, 126, 172, 172, 342, 342, 374, 380, 464, 464, 464, 464, 464, 464, 464, 464, 847, 847, 1056, 1105, 1105, 1105, 1105, 1105, 1330, 1330, 1728, 1728, 1728, 1728, 1728, 2410, 2856, 2856, 2856, 2856
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OFFSET
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1,2
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COMMENTS
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Values in a(n): 1, 2, 6, 8, 20, 28, 36, 56, 90, 120, 126, 172, 342, 374, 380, 464, 847, 1056, 1105, 1330, 1728, 2410, 2856, ...
First position of values in a(n): 1, 2, 3, 4, 5, 7, 8, 10, 11, 13, 14, 17, 19, 21, 22, 23, 31, 33, 34, 39, 41, 46, 47, ...
(End)
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LINKS
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EXAMPLE
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a(4) = 8 because A000005(8!) = 96 is divisible by 4! = 24.
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MATHEMATICA
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Table[k = 1; While[! Divisible[DivisorSigma[0, k!], n!], k++]; k, {n, 50}] (* Michael De Vlieger, Aug 10 2016 *)
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PROG
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(PARI) a(n) = {my(k=1); while(numdiv(k!) % n!, k++); k; }
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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