A127092 Numbers k such that k^2 divides 11^k - 1.

1, 2, 4, 5, 6, 10, 12, 20, 30, 42, 60, 84, 114, 156, 210, 222, 228, 244, 420, 444, 570, 732, 780, 798, 930, 1092, 1110, 1140, 1220, 1554, 1596, 1806, 1860, 2220, 2436, 2964, 3108, 3612, 3660, 3990, 4218, 5124, 5460, 5772, 6510, 7770, 7980, 8268, 8436, 9030

Offset: 1

Author

Alexander Adamchuk, Jan 05 2007

Keywords

• nonn

Comments

Subsequence of A068383.

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..1000

Crossrefs

Column k=11 of A333500.

Cf. A068383, A127100, A127101, A127102, A127104, A127105, A127106, A127107, A292336.

Programs

Mathematica

Select[Range[15000], IntegerQ[(PowerMod[11, #, #^2 ]-1)/#^2 ]&]
Join[{1},Select[Range[9100],PowerMod[11,#,#^2]==1&]] (* Harvey P. Dale, Dec 30 2018 *)

PARI

for(k=1, 1e4, if(Mod(11, k^2)^k==1, print1(k", "))) \\ Seiichi Manyama, Mar 25 2020