A071422 a(n) = a(n-1) + sum of decimal digits of sigma(n), the sum of divisors of n.

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

Offset: 1

Author

Labos Elemer, May 27 2002

Keywords

• base
• easy
• nonn

Links

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

Crossrefs

Cf. A037123, A000788, A051351.

Partial sums of A067342.

Programs

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 *)