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Search: id:A118813
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| A118813 |
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Primes of the form (2n)! - n! - 1. |
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+0
1
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| 3628679, 87178286159, 20922789847679, 265252859812191058635000805631999
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The next term is too large to include.
All the numbers end in 9
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EXAMPLE
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n=5 (2*5)! - 5! - 1 = 3628800 - 120 - 1 = 3628679
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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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Adjacent sequences: A118810 A118811 A118812 this_sequence A118814 A118815 A118816
Sequence in context: A107349 A053078 A116221 this_sequence A127229 A068158 A011521
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KEYWORD
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nonn
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AUTHOR
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Paolo P. Lava and Giorgio Balzarotti (ppl(AT)spl.at), May 23 2006
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