A235868 Union of 2 and powers of odd primes.

1, 2, 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 27, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 125, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229

Offset

1,2

Comments

Numbers n such that the group G_n:={x+yi: x^2+y^2==1 (mod n); 0<=x,y<n} is cyclic; i.e., numbers n such that A060968(n) = A235863(n).

Links

Table of n, a(n) for n=1..59.

Jose María Grau, A. M. Oller-Marcen, Manuel Rodriguez and D. Sadornil, Fermat test with Gaussian base and Gaussian pseudoprimes, arXiv:1401.4708 [math.NT], 2014.

Formula

{2} UNION A061345. - R. J. Mathar, Jul 19 2024

Mathematica

Select[ Range[230], # == 2 || Mod[#, 2] == 1 && PrimeNu[#] < 2 &] (* and modified by Robert G. Wilson v, Dec 29 2016 *)

Crossrefs

Cf. A060968, A061345, A235863.

Sequence in context: A279516 A329559 A305081 * A319151 A180934 A090332

Adjacent sequences: A235865 A235866 A235867 * A235869 A235870 A235871

Keyword

nonn

Author

José María Grau Ribas, Feb 23 2014

Status

approved