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A071422
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a(n) = a(n-1) + sum of decimal digits of sigma(n), the sum of divisors of n.
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1
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1, 4, 8, 15, 21, 24, 32, 38, 42, 51, 54, 64, 69, 75, 81, 85, 94, 106, 108, 114, 119, 128, 134, 140, 144, 150, 154, 165, 168, 177, 182, 191, 203, 212, 224, 234, 245, 251, 262, 271, 277, 292, 300, 312, 327, 336, 348, 355, 367, 379, 388, 405, 414, 417, 426, 429
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listen;
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internal format)
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OFFSET
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1,2
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LINKS
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Harvey P. Dale, Table of n, a(n) for n = 1..1000
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MATHEMATICA
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s=0; Do[s=s+Apply[Plus, IntegerDigits[DivisorSigma[1, n]]]; Print[s], {n, 1, 128}]
nxt[{n_, a_}]:={n+1, a+Total[IntegerDigits[DivisorSigma[1, n+1]]]}; Transpose[ NestList[nxt, {1, 1}, 60]][[2]] (* Harvey P. Dale, Jan 25 2013 *)
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CROSSREFS
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Cf. A037123, A000788, A051351.
Sequence in context: A312751 A312752 A312753 * A212538 A113902 A024916
Adjacent sequences: A071419 A071420 A071421 * A071423 A071424 A071425
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KEYWORD
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base,easy,nonn
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AUTHOR
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Labos Elemer, May 27 2002
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STATUS
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approved
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