A241978 Numbers n such that 6^phi(n) == 1 (modulo n^2), where phi(n) is Euler's totient function.

66161, 330805, 534851, 2674255, 3152573, 10162169, 13371275, 50810845, 54715147, 129255493, 148170931, 254054225, 273575735, 301121113, 383006029, 646277465, 1289402357, 1505605565, 1915030145, 3228193673, 3407931413, 5721301147, 6075008171, 7528027825

Offset

1,1

Comments

a(17) > 10^9.

Links

Giovanni Resta, Table of n, a(n) for n = 1..95 (terms < 10^14)

Mathematica

Select[Range[65*10^7], PowerMod[6, EulerPhi[#], #^2]==1&] (* Harvey P. Dale, Jan 20 2020 *)

Prog

(PARI) for(n=2, 1e9, if(Mod(6, n^2)^(eulerphi(n))==1, print1(n, ", ")))

Crossrefs

Cf. A000010, A077816, A212583, A242958, A242959, A242960, A241977, A245529.

Sequence in context: A254192 A254185 A253797 * A212583 A156424 A092376

Adjacent sequences: A241975 A241976 A241977 * A241979 A241980 A241981

Keyword

nonn

Author

Felix Fröhlich, Aug 10 2014

Extensions

Terms a(17) and beyond from Giovanni Resta, Jan 24 2020

Status

approved