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Search: id:A139425
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| A139425 |
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Smallest number k such that M(n)^2-k*M(n)+1 is prime with M(n)= Mersenne primes =A000668(n). |
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+0
8
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| 1, 1, 9, 3, 3, 25, 7, 21, 435, 241, 3, 153, 151, 493, 537, 2871, 1713, 4941, 4963, 307, 28413, 5035, 1615, 43525, 9973
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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All primes certified using openpfgw_v12 from primeform group
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EXAMPLE
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3*3-1*3+1=7 prime 3=M(1)=2^2-1 so k(1)=1
7*7-1*7+1=43 prime 7=M(2)=2^3-1 so k(2)=1
31*31-9*31+1=683 prime 31=M(3)=2^5-1 so k(3)=9
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CROSSREFS
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Cf. A000668, A139424, A139426, A139427, A139428, A139429, A139430, A139421.
Sequence in context: A037921 A019878 A097902 this_sequence A090485 A021521 A011011
Adjacent sequences: A139422 A139423 A139424 this_sequence A139426 A139427 A139428
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KEYWORD
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hard,more,nonn
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AUTHOR
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Pierre CAMI (pierrecami(AT)tele2.fr), Apr 21 2008
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