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A125956
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Numbers n such that (2^n + 9^n)/11 is prime.
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OFFSET
| 1,1
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COMMENTS
| All terms are primes. Note that first 3 terms (3, 7, 127} are primes of the form 2^q - 1, where q = {2, 3, 7) is prime too. Corresponding primes of the form (2^n + 9^n)/11 are {67, 434827, ...}.
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MATHEMATICA
| Do[p=Prime[n]; f=(2^p+9^p)/11; If[PrimeQ[f], Print[{p, f}]], {n, 1, 100}]
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CROSSREFS
| Cf. A000978 = numbers n such that (2^n + 1)/3 is prime. Cf. A057469 = numbers n such that (2^n + 3^n)/5 is prime. Cf. A082387 = numbers n such that (2^n + 5^n)/7 is prime.
Sequence in context: A066771 A139159 A042329 * A128071 A079622 A005844
Adjacent sequences: A125953 A125954 A125955 * A125957 A125958 A125959
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KEYWORD
| hard,more,nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 06 2007
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EXTENSIONS
| 2 more terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Feb 14 2007
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