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Search: id:A074120
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| A074120 |
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Group successively larger composite numbers so that the sum of the n-th group is a multiple of n. Sequence gives the sum of the terms in the n-th group. |
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4
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| 4, 6, 27, 12, 45, 18, 63, 24, 270, 330, 198, 780, 2314, 644, 1800, 3600, 3808, 3150, 6479, 3500, 7140, 2662, 2438, 936, 5175, 6526, 1431, 8596, 12586, 8730, 7812, 20768, 3663, 38488, 13020, 16848, 1998, 10830, 21099, 39840, 4715, 60732, 15953
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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(4), (6), (8, 9, 10), (12), (14, 15, 16), (18), (20, 21, 22), (24), (25, 26, 27, 28, 30, 32, 33, 34, 35), (36, 38, 39, 40, 42, 44, 45, 46), (48, 49, 50, 51), ...
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MATHEMATICA
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NextComposite[n_] := Block[{k = n + 1}, While[PrimeQ[k], k++ ]; k]; a = {}; k = 1; Do[s = 0; While[k = NextComposite[k]; s = s + k; !IntegerQ[s/n], ]; a = Append[a, s], {n, 1, 45}]; a
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CROSSREFS
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Cf. A002808, A074128, A074121, A074122 A074123.
Sequence in context: A054094 A123873 A099941 this_sequence A054265 A105409 A109934
Adjacent sequences: A074117 A074118 A074119 this_sequence A074121 A074122 A074123
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 27 2002
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EXTENSIONS
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Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 29 2002
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