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Search: id:A118812
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| A118812 |
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Primes of the form (2n)! - n! + 1. |
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+0 1
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| 2, 23, 87178286161, 403291461126605629356979201, 5502622159812088949850305428800254867109635014075023360001
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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n=2 (2*2)! - 2! + 1 = 24 - 2 + 1 = 23
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MAPLE
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PFACT:=proc(N) local i, r; for i from 1 by 1 to N do r:=(2*i)!-i!+1; if isprime(r) then print(i); fi; od; end: PFACT(100);
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CROSSREFS
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Sequence in context: A067837 A089987 A162605 this_sequence A054909 A100816 A079612
Adjacent sequences: A118809 A118810 A118811 this_sequence A118813 A118814 A118815
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KEYWORD
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nonn
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AUTHOR
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Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), May 23 2006
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