A225148 Primes of the form (k^p-1)/(k-1) not having representation in the form (m^q+1)/(m+1), where k,m > 1 and p,q > 2.

127, 1093, 2801, 19531, 22621, 30941, 55987, 88741, 131071, 245411, 292561, 346201, 524287, 637421, 732541, 797161, 837931, 2625641, 3500201, 3835261, 5229043, 6377551, 8108731, 12207031, 15018571, 16007041, 21700501, 25646167, 28792661, 30397351, 35615581

Offset: 1

Author

Thomas Ordowski, Apr 30 2013

Keywords

• nonn

Comments

The exponent p must be a prime p > 3. If p=3 then (k^p-1)/(k-1) = (m^q+1)/(m+1) for m=k+1 and q=3.

Are almost all primes of the form (k^p-1)/(k-1), where k > 1 and p > 3, in the sequence? Except 31 and 8191. See:

31 = (2^5-1)/(2-1) = (5^3-1)/(5-1) = (6^3+1)/(6+1),

8191 = (2^13-1)/(2-1) = (90^3-1)/(90-1) = (91^3+1)/(91+1).

Crossrefs

Cf. A085104, A059055.

Formula

Numbers in A085104 but not in A059055.

Extensions

Extended by T. D. Noe, Apr 30 2013