%I #14 Jun 30 2021 02:32:38
%S 1,18,19,30,31,48,50,67,68,79,80,97,99,116,117,128,129,146,148,165,
%T 166,177,178,195,197,214,215,226,227,244,246,263,264,275,276,293,295,
%U 312,313,324,325,342,344,361,362,373,374,391,393,410,411,422,423,440,442
%N Numbers k such that k^6 == 1 (mod 7^2).
%H Amiram Eldar, <a href="/A056022/b056022.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[ Range[ 500 ], PowerMod[ #, 6, 49 ]==1& ]
%o (PARI) isok(k) = Mod(k, 49)^6 == 1; \\ _Michel Marcus_, Jun 30 2021
%Y Cf. A056021, A056024, A056025, A056026, A056027, A056028, A056031, A056034, A056035.
%K nonn,easy
%O 1,2
%A _Robert G. Wilson v_, Jun 08 2000