A305331 Multiplicative order of 5 (mod p^2), where p = prime(n), or 0 if 5 and p are not coprime.

1, 6, 0, 42, 55, 52, 272, 171, 506, 406, 93, 1332, 820, 1806, 2162, 2756, 1711, 1830, 1474, 355, 5256, 3081, 6806, 3916, 9312, 2525, 10506, 11342, 2943, 12656, 5334, 8515, 18632, 9591, 5513, 11325, 24492, 8802, 27722, 29756, 15931, 2715, 3629, 37056, 38612

Offset: 1

Author

Felix Fröhlich, May 30 2018

Keywords

• nonn

Crossrefs

Cf. A211241, A305332, A305333.

Programs

Mathematica

Table[If[p==5, 0, MultiplicativeOrder[5, p^2]], {p, Prime@ Range@ 45}] (* Giovanni Resta, May 31 2018 *)

PARI

a(n) = my(p=prime(n)); if(p==5, return(0), return(znorder(Mod(5, p^2))))