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A067204 Numbers k such that sigma(sigma(k)) == phi(k) (mod sigma(k)). 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 11 03:41 EDT 2022. Contains 356046 sequences. (Running on oeis4.)