A242959 Numbers n such that 5^A000010(n) == 1 (mod n^2).

2, 20771, 40487, 41542, 80974, 83084, 161948, 643901, 1255097, 1287802, 1391657, 1931703, 2510194, 2575604, 2783314, 3765291, 3863406, 4174971, 5020388, 5151208, 5566628, 7530582, 7726812, 8349942, 10040776, 11133256, 15061164, 15308227, 15453624, 16699884

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..479 (terms < 10^15, first 75 terms from Felix Fröhlich)

Mathematica

Select[Range[167*10^5], PowerMod[5, EulerPhi[#], #^2]==1&] (* Harvey P. Dale, Jun 02 2020 *)

Prog

(PARI) for(n=2, 10^9, if(Mod(5, n^2)^(eulerphi(n))==1, print1(n, ", ")))

Crossrefs

Cf. A077816, A242958, A242960.

If a(n) is prime, then a(n) is in A123692.

Sequence in context: A214598 A346988 A339476 * A123692 A290741 A261362

Adjacent sequences: A242956 A242957 A242958 * A242960 A242961 A242962

Keyword

nonn

Author

Felix Fröhlich, May 27 2014

Status

approved