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A140797
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Numbers of the form (2^p^N-1)/(2^p^(N-1)-1), where N>0, p is prime.
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2
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3, 5, 7, 17, 31, 73, 127, 257, 2047, 8191, 65537, 131071, 262657, 524287, 1082401, 8388607, 536870911, 2147483647, 4294967297, 137438953471, 2199023255551, 4432676798593, 8796093022207, 140737488355327, 9007199254740991, 18014398643699713, 576460752303423487
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Contains Fermat numbers A000215 (p=2) and Mersenne numbers A001348 (N=1). The terms of the sequence are either primes A000040 or overpseudoprimes A141232.
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
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REFERENCES
| V. Shevelev, Process of "primoverization" of numbers of the form a^n-1, http:// arxiv.org/abs/0807.2332
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..199
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CROSSREFS
| Cf. A000040 A000215 A001348 A141232.
Sequence in context: A174394 A057476 A016041 * A038893 A191064 A075227
Adjacent sequences: A140794 A140795 A140796 * A140798 A140799 A140800
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KEYWORD
| nonn
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AUTHOR
| Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jul 15 2008
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EXTENSIONS
| Definition corrected by and more terms from T. D. Noe, Jul 21 2008
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