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A073443
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Numbers n such that n! - n - 1 is prime.
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1
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OFFSET
| 1,1
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COMMENTS
| Clearly n <> 2 (mod 3). For n>3, n!-n, n!-n+1, ..., n!-3, n!-2 is a sequence of n-1 consecutive composite numbers. Additional terms are greater than 2000.
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MATHEMATICA
| Select[Range[3, 346], PrimeQ[#! - # - 1] &] (* Arkadiusz Wesolowski, Jan 04 2012 *)
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PROG
| (PARI) for(n=3, 2000, if(isprime(n!-n-1), print1(n, ", ")))
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CROSSREFS
| Cf. A073444 (corresponding primes), A002982 (n!-1 is prime), A073308 (n!+n+1 is prime).
Sequence in context: A101506 A092434 A031367 * A092119 A143372 A035594
Adjacent sequences: A073440 A073441 A073442 * A073444 A073445 A073446
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KEYWORD
| nonn
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AUTHOR
| Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 31 2002
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EXTENSIONS
| Offset corrected by Arkadiusz Wesolowski, Jan 04 2012
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