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Search: id:A057732
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| A057732 |
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Numbers n such that 2^n + 3 is prime. |
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+0
15
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| 1, 2, 3, 4, 6, 7, 12, 15, 16, 18, 28, 30, 55, 67, 84, 228, 390, 784, 1110, 1704, 2008, 2139, 2191, 2367, 2370, 4002, 4060, 4062, 4552, 5547, 8739, 17187, 17220, 17934, 20724, 22732, 25927, 31854, 33028, 35754, 38244, 39796, 40347, 55456, 58312, 122550
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Some of the larger entries may only correspond to probable primes.
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REFERENCES
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Mike Oakes, posting to primenumbers(AT)yahoogroups.com on Jul 08 2001
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MATHEMATICA
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Clear[f, n]; f[n_]:=PrimeQ[2^n+3]; lst={}; Do[If[f[n], AppendTo[lst, n]], {n, 8!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 02 2009]
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PROGRAM
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(PARI) j=[]; for(n=1, 2200, if(isprime(2^n+3), j=concat(j, n))); j
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CROSSREFS
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Cf. A050414 (2^n-3 is prime).
Sequence in context: A057128 A018534 A018276 this_sequence A092591 A039947 A096477
Adjacent sequences: A057729 A057730 A057731 this_sequence A057733 A057734 A057735
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KEYWORD
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nice,nonn
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AUTHOR
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G. L. Honaker, Jr. (honak3r(AT)gmail.com), Oct 29 2000
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EXTENSIONS
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More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jul 18 2001 and Mike Oakes (mikeoakes2(AT)aol.com), Jul 28 2001
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