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Search: id:A129963
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| A129963 |
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Primes of the form 4^n + n. |
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+0
1
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| 5, 67, 262153, 1073741839, 18889465931478580854821, 1496577676626844588240573268701473812127674924007509, 11857109937901178411373668864889641764174846429761593757640456602410304475129459\ 7
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is convenient, although not necessary, to let n be an odd number since n even => 4^n + n is even > 2. Conjecture: There is an infinite number of primes in this sequence.
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EXAMPLE
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For n = 3, 4^3+3=67 is prime.
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PROGRAM
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(PARI) f(n) = for(x=1, n, y=2^x+x; if(isprime(y), print1(y", ")))
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CROSSREFS
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Sequence in context: A123034 A166619 A113064 this_sequence A115764 A003361 A099334
Adjacent sequences: A129960 A129961 A129962 this_sequence A129964 A129965 A129966
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)hotmail.com), Jun 10 2007, Aug 20 2007
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