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Search: id:A137907
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| A137907 |
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Least k such that k*(2^p-1)*(k*(2^p-1)-1)+1 is prime, where 2^p-1 runs through the Mersenne primes. |
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+0
4
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| 1, 1, 9, 6, 9, 24, 4, 7, 28, 70, 73, 121, 511, 106, 343, 2169, 1423, 2146, 5736, 4444, 2484, 2310, 26, 79, 25623, 2481, 39213
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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1*(2^2-1)*(1*(2^2-1)-1)+1=7 prime, 2^2-1 first Mersenne prime, k(1)=1
1*(2^3-1)*(1*(2^3-1)-1)+1=43 prime, 2^3-1 second Mersenne prime, k(2)=1
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CROSSREFS
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Cf. A137906, A137908, A137909.
Sequence in context: A010545 A019790 A146486 this_sequence A070164 A063602 A166520
Adjacent sequences: A137904 A137905 A137906 this_sequence A137908 A137909 A137910
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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), Feb 22 2008
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