A272361 Numbers n such that (2^n + 1) / gcd(n, 2^n + 1) is not squarefree.

182, 546, 910, 1274, 1638, 2002, 2366, 2730, 3094, 3458, 3822, 4186, 4550, 4914, 5278, 5642, 6006, 6370, 6734, 7098, 7462, 7826, 8190, 8554, 8918, 9282, 9646, 10010, 10374, 10738, 11102, 11466, 11830, 12194, 12558, 12922, 13286, 13650, 14014, 14378, 14742, 15106, 15470, 15834

Offset: 1

Author

Thomas Ordowski, Apr 27 2016

Keywords

• nonn

Comments

Odd multiples of integer A002326((q-1)/2)/2, where q is a Wieferich prime A001220.

Crossrefs

Cf. A049096, A272359.

Programs

PARI

isok(n) = my(m=2^n+1); !issquarefree(m/gcd(n, m)); \\ Michel Marcus, Apr 27 2016