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A120679
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a(1)=1. a(n) = a(n-1) + d(a(k)), where d(m) is the number of positive divisors of m and d(a(k)) is the maximum value over the k's where 1<=k <=n-1.
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2
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1, 2, 4, 7, 10, 14, 18, 24, 32, 40, 48, 58, 68, 78, 88, 98, 108, 120, 136, 152, 168, 184, 200, 216, 232, 248, 264, 280, 296, 312, 328, 344, 360, 384, 408, 432, 456, 480, 504, 528, 552, 576, 600, 624, 648, 672, 696, 720, 750, 780, 810, 840, 872, 904, 936, 968
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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EXAMPLE
| The number of positive divisors of the first 13 terms of this sequence form the sequence 1,2,3,2,4,4,6,8,6,8,10,4,6 (sequence A120680). Of these terms, 10 is the largest. So a(14) = a(13) + 10 = 78.
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MAPLE
| A120679 := proc(maxn) local d, p, a, n; a := [1] ; d := 1 ; for n from 2 to maxn do d := max(d, numtheory[tau](a[n-1])) ; a := [op(a), a[n-1]+d] ; od ; RETURN(a) ; end: nmax := 80 : a := A120679(nmax) : for n from 1 to nmax do printf("%d, ", a[n]) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 17 2006
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CROSSREFS
| Cf. A120680.
Sequence in context: A184674 A183136 A144873 * A145106 A127723 A076268
Adjacent sequences: A120676 A120677 A120678 * A120680 A120681 A120682
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Jun 24 2006
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 17 2006
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