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A067733 Numbers k such that phi(prime(k)-1) == 0 (mod k). 0
1, 12, 540, 1024, 1072, 1092, 1320, 1408, 4272, 16200, 29568, 40082, 43740, 56592, 123192, 251736, 265440, 276000, 664320, 725760, 758560, 771264, 2101248, 3195192, 6592704, 7243050, 7464960, 8755680, 10553502, 11715840, 14135296, 19952730, 20058720, 21672288 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..34.

MATHEMATICA

Select[Range[42000], Mod[EulerPhi[Prime[ # ] - 1], # ] == 0 &]

PROG

(PARI) for(k=1, 2600000, if(eulerphi(prime(k)-1)%k==0, print1(k, ", ")))

CROSSREFS

Cf. A000010, A006093, A008330.

Sequence in context: A296685 A281030 A282589 * A285748 A184423 A064344

Adjacent sequences:  A067730 A067731 A067732 * A067734 A067735 A067736

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 05 2002

EXTENSIONS

More terms from Klaus Brockhaus, Feb 13 2002

More terms from Jinyuan Wang, Apr 05 2020

STATUS

approved

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Last modified January 25 00:44 EST 2022. Contains 350565 sequences. (Running on oeis4.)