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Search: id:A119550
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| A119550 |
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Prime numbers of the form 2^(2^n) + 2^n - 1. |
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+0
2
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OFFSET
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1,1
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FORMULA
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Define F(n) = 2^(2^n)+1 = n-th Fermat number, M(n) = 2^n-1 = the n-th Mersenne number. Then we are considering the numbers f(n) = F(n)+M(n)-1 = 2^(2^n) + 2^n - 1 (cf. A119563).
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EXAMPLE
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F(2)= 2^(2^2)+1 = 17, M(2) = 2^2-1 = 3, F(2)+ M(2)-1 = 19 is prime, so 2 is a member.
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PROGRAM
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(PARI) fmp3(n)=for(x=0, n, y=2^(2^x)+2^x-1; if(ispseudoprime(y), print1(y", ")))
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CROSSREFS
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Cf. A119563, A119564.
Sequence in context: A085871 A080280 A055813 this_sequence A119563 A059079 A136900
Adjacent sequences: A119547 A119548 A119549 this_sequence A119551 A119552 A119553
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KEYWORD
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nonn,more,less
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), May 31 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Jun 03 2006
Definition corrected by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 10 2007
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