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Search: id:A118743
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| A118743 |
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Primes of the form n!! + n + 1. |
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+0
1
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| 3, 5, 7, 13, 113, 3851, 46093, 10321937, 185794579, 216862434431944426122117120047, 1874480713189654839282450157086195210900931486780353469173376681742503659434414632312033372643386765197475111737132341321962070865661132800000000000000000173
(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 + 1 = 2 + 2 + 1 = 5
n=4 4!! + 4 + 1 = 4*2 + 4 + 1 = 8 + 4 + 1 = 13
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MAPLE
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SFACT:= proc(n) local i, j, k; for k from 1 by 1 to n do i:=k; j:=k-2; while j >0 do i:=i*j; j:=j-2; od: if isprime(i+k+1) then print(i+k+1); fi; od: end: SFACT(550);
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CROSSREFS
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Sequence in context: A057187 A141414 A064268 this_sequence A114980 A024372 A061390
Adjacent sequences: A118740 A118741 A118742 this_sequence A118744 A118745 A118746
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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 22 2006
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