A234952 Apply the map k -> L(k)/gcd(L(k),k-1) to the sequence A007850 of Giuga numbers, where L(k) is the Carmichael lambda function A002322.

4, 60, 120, 2320, 1552848, 10080, 139714902540, 93294624780, 228657996794220, 4756736241732916394976, 20024071474861042488900, 2176937111336664570375832140, 15366743578393906356665002406454800354974137359272445859047945613961394951904884493965220

Offset: 1

Author

N. J. A. Sloane, Jan 12 2014

Keywords

• nonn

Links

• J. M. Grau and A. M. Oller-Marcén, On the congruence sum_{j=1}^{n-1} j^{k(n-1)} == -1 (mod n); k-strong Giuga and k-Carmichael numbers, arXiv preprint arXiv:1311.3522, 2013

Crossrefs

Cf. A007850, A002322.