A067204 Numbers k such that sigma(sigma(k)) == phi(k) (mod sigma(k)).

2, 26, 77, 85, 194, 335, 707, 1350, 2443, 2639, 9158, 9602, 15238, 16625, 19698, 23199, 24416, 52328, 54663, 56927, 64206, 67226, 69875, 82235, 100837, 104489, 136213, 150040, 161268, 230216, 244572, 251488, 271215, 273208, 283492, 298205, 306878, 352660

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..500

Prog

(PARI) for(n=1, 10^8, s=sigma(n); if(sigma(s)%s==eulerphi(n), print(n))) \\ Donovan Johnson, Feb 25 2013

Crossrefs

Sequence in context: A345693 A229573 A337396 * A202077 A280212 A120551

Adjacent sequences: A067201 A067202 A067203 * A067205 A067206 A067207

Keyword

nonn

Author

Benoit Cloitre, Feb 19 2002

Status

approved