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A071422 a(n) = a(n-1) + sum of decimal digits of sigma(n), the sum of divisors of n. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

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 *)

CROSSREFS

Cf. A037123, A000788, A051351.

Sequence in context: A312751 A312752 A312753 * A212538 A113902 A024916

Adjacent sequences:  A071419 A071420 A071421 * A071423 A071424 A071425

KEYWORD

base,easy,nonn

AUTHOR

Labos Elemer, May 27 2002

STATUS

approved

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Last modified July 18 11:30 EDT 2019. Contains 325138 sequences. (Running on oeis4.)