A067064 Numbers n such that sigma(sigma(sigma(n))) == 0 (mod sigma(n)).

1, 3, 7, 8, 14, 15, 20, 23, 24, 26, 38, 41, 44, 59, 60, 65, 78, 83, 92, 114, 123, 132, 133, 135, 140, 143, 158, 167, 168, 177, 182, 188, 195, 203, 204, 209, 220, 224, 239, 246, 248, 249, 266, 284, 285, 286, 287, 297, 299, 334, 378, 381, 395, 413, 415, 420, 437

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[500], Divisible[DivisorSigma[1, DivisorSigma[1, DivisorSigma[ 1, #]]], DivisorSigma[ 1, #]]&] (* Harvey P. Dale, Oct 04 2017 *)

Prog

(PARI) { n=0; for (m=1, 10^10, if (sigma(sigma(sigma(m))) % sigma(m) == 0, write("b067064.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, May 02 2010

Crossrefs

Sequence in context: A279517 A106474 A127441 * A093722 A309745 A002381

Adjacent sequences: A067061 A067062 A067063 * A067065 A067066 A067067

Keyword

nonn

Author

Benoit Cloitre, Feb 17 2002

Status

approved