A067696 Numbers k such that prime(k) == -1 (mod sigma(k)).

1, 5, 13, 15, 31, 39, 49, 96, 111, 205, 215, 452, 492, 712, 1258, 5599, 10170, 11514, 32844, 58841, 59550, 83251, 83650, 115139, 120485, 144835, 152583, 467583, 709178, 1617217, 3101711, 3554345, 3714335, 6580179, 8099488

Offset

1,2

Links

Table of n, a(n) for n=1..35.

Mathematica

Do[s=(Prime[n]+1)/DivisorSigma[1, n]; If[IntegerQ[s], Print[n]], {n, 1000000, 10000000}
Select[Range[81*10^5], Mod[Prime[#]+1, DivisorSigma[1, #]]==0&] (* Harvey P. Dale, May 03 2018 *)

Crossrefs

Cf. A067697, A071170.

Sequence in context: A322105 A230503 A335695 * A050598 A297862 A298129

Adjacent sequences: A067693 A067694 A067695 * A067697 A067698 A067699

Keyword

nonn

Author

Benoit Cloitre, Feb 05 2002

Extensions

More terms from Labos Elemer, Jun 12 2003

Status

approved