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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. 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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).

LINKS

Table of n, a(n) for n=1..31.

FORMULA

Numbers in A085104 but not in A059055.

CROSSREFS

Cf. A085104, A059055.

Sequence in context: A253925 A196658 A077361 * A160897 A038994 A068023

Adjacent sequences:  A225145 A225146 A225147 * A225149 A225150 A225151

KEYWORD

nonn

AUTHOR

Thomas Ordowski, Apr 30 2013

EXTENSIONS

Extended by T. D. Noe, Apr 30 2013

STATUS

approved

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Last modified April 16 18:53 EDT 2021. Contains 343050 sequences. (Running on oeis4.)