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A082672
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Numbers n such that (n!+2)/2 is a prime.
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44
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2, 4, 5, 7, 8, 13, 16, 30, 43, 49, 91, 119, 213, 1380, 1637, 2258, 4647, 9701, 12258
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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MATHEMATICA
| Select[Range[10^2], PrimeQ[(#!+2)/2] &] (from Vladimir Orlovsky (4vladimir(AT)gmail.com), Apr 29 2008)
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PROG
| (PARI) \ x such that (x!+2)/2 is prime xfactpk(n, 2) = { for(x=2, n, y = (x!+k)/k; if(isprime(y), print1(x" ")) ) }
(MAGMA) [ n: n in [1..300] | IsPrime((Factorial(n)+2) div 2) ];
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CROSSREFS
| Cf. A089130.
Sequence in context: A107899 A032924 A005125 * A187054 A135693 A135367
Adjacent sequences: A082669 A082670 A082671 * A082673 A082674 A082675
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KEYWORD
| easy,nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), May 18 2003
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EXTENSIONS
| More terms from Don Reble, Dec 08 2003
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
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