A067733 Numbers k such that phi(prime(k)-1) == 0 (mod k).

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

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 * A353194 A285748 A184423

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