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A074122
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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 number of terms in the n-th group.
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3
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1, 1, 3, 1, 3, 1, 3, 1, 9, 8, 4, 13, 27, 6, 15, 25, 22, 16, 29, 14, 26, 9, 8, 3, 16, 19, 4, 23, 31, 20, 17, 42, 7, 68, 21, 26, 3, 16, 30, 53, 6, 73, 18, 84, 19, 26, 77, 32, 5, 83, 3, 55, 16, 107, 1, 44, 5, 40, 7, 207, 17, 41, 17, 14, 23, 49, 100, 46, 34, 36, 47, 216, 50, 17, 7, 58
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| a(n) = 1 for n: 1,2,4,6,8,55,154,616,(10^4).
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EXAMPLE
| (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
| NextComposite[n_] := Block[{k = n + 1}, While[PrimeQ[k], k++ ]; k]; a = {}; k = 1; Do[s = 0; c = 0; While[k = NextComposite[k]; s = s + k; !IntegerQ[s/n], c++ ]; a = Append[a, c + 1], {n, 1, 80}]; a
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CROSSREFS
| Cf. A002808, A074130, A074120, A074121, A074123.
Sequence in context: A035689 A050345 A070039 * A135023 A087822 A163378
Adjacent sequences: A074119 A074120 A074121 * A074123 A074124 A074125
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 27 2002
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EXTENSIONS
| Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 29 2002
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