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Search: id:A075422
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| A075422 |
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Primitive numbers such that n! divided by product of factorials of all proper divisors of n is not an integer. |
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+0
3
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| 24, 30, 36, 40, 54, 84, 100, 102, 112, 126, 132, 140, 156, 176, 198, 208, 220, 228, 234, 260, 272, 276, 294, 308, 340, 342, 348, 350, 364, 372, 380, 392, 414, 444, 460, 462, 476, 490, 492, 516, 522, 532, 546, 558, 564, 572, 580, 608, 620, 636, 644, 666, 708
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Once in the sequence all of its multiples also meet the criteria but are not included.
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FORMULA
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a(n) appears to be asymptotic to c*n with 12<c<15 - Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 16 2002
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MATHEMATICA
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f[n_] := n!/Apply[Times, Drop[Divisors[n], -1]! ]; a = {}; Do[b = f[n]; If[ !IntegerQ[b], If[ Select[n/a, IntegerQ] == {}, a = Append[a, n]]], {n, 1, 725}]; a
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CROSSREFS
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Cf. A075071. The first several odd primitive n's are in A075460.
Sequence in context: A114635 A077969 A122181 this_sequence A098030 A068544 A109797
Adjacent sequences: A075419 A075420 A075421 this_sequence A075423 A075424 A075425
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com) & Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 14 2002
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