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Search: id:A060742
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| A060742 |
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Number of divisors of n! which are also differences between consecutive divisors of n! (ordered by size). |
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+0
7
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| 0, 0, 1, 2, 4, 9, 15, 27, 41, 68, 111, 218, 328, 624, 929, 1518, 2016, 3689, 4965, 9252, 13177, 20016, 30697, 56749, 69434, 94242, 149558, 190292, 258370, 492924, 615063, 1149403, 1325124
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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D. Berend et al. (1993): Gaps between consecutive divisors of factorials, Ann. Inst. Fourier, 43(3):569-583.
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EXAMPLE
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For n=5, n!=120; divisors={1,2,3,4,5,6,8,10,12,15,20,24,30,40,60,120}; differences={1,1,1,1,1,2,2,2,3,5,4,6,10,20,60}; intersection={1,2,3,4,5,6,10,20,60}, so a(5)=9.
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MATHEMATICA
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a[n_ ] := Length[Intersection[Drop[d=Divisors[n! ], 1]-Drop[d, -1], d]]
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CROSSREFS
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Cf. A000142, A027423, A060737, A060738, A060741.
Sequence in context: A072846 A157254 A080004 this_sequence A060737 A085683 A083270
Adjacent sequences: A060739 A060740 A060741 this_sequence A060743 A060744 A060745
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Apr 23 2001
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EXTENSIONS
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Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Jan 22 2002
One more term from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 29 2002
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