%I A140797
%S A140797 3,5,7,17,31,73,127,257,2047,8191,65537,131071,262657,524287,1082401,8388607,
%T A140797 536870911,2147483647,4294967297,137438953471,2199023255551,4432676798593,
%U A140797 8796093022207,140737488355327,9007199254740991,18014398643699713,576460752303423487
%N A140797 Numbers of the form (2^p^N-1)/(2^p^(N-1)-1), where N>0, p is prime.
%C A140797 Contains Fermat numbers A000215 (p=2) and Mersenne numbers A001348 (N=1). 
               The terms of the sequence are either primes A000040 or overpseudoprimes 
               A141232.
%C A140797 The values of A019320(n) for prime power n, sorted. This sequence is 
               a subsequence of A064896, which means that all terms are sturdy numbers 
               (A125121). It appears that the largest prime factor of each of these 
               numbers is a sturdy prime (A143027). - T. D. Noe, Jul 21 2008
%D A140797 V. Shevelev, Process of "primoverization" of numbers of the form a^n-1, 
               http:// arxiv.org/abs/0807.2332
%H A140797 T. D. Noe, <a href="b140797.txt">Table of n, a(n) for n=1..199</a>
%Y A140797 Cf. A000040 A000215 A001348 A141232.
%Y A140797 Sequence in context: A002092 A057476 A016041 this_sequence A038893 A075227 
               A064080
%Y A140797 Adjacent sequences: A140794 A140795 A140796 this_sequence A140798 A140799 
               A140800
%K A140797 nonn
%O A140797 1,1
%A A140797 Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jul 15 2008
%E A140797 Definition corrected by and more terms from T. D. Noe, Jul 21 2008