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Search: id:A130309
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| A130309 |
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Primes of the form [n!! - (n-1)!! + (n-2)!! -....1!! ]+1. |
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+0
2
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| 2, 3, 7, 67, 153979499670311863, 96139392052480758114443739387402080695373863
(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.
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EXAMPLE
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2 = 1!! + 1 or 2!! - 1!! + 1.
7 = 4!! - 3!! + 2!! - 1!! +1 = 8 - 3 + 2 - 1 + 1.
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MAPLE
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P:=proc(n) local a, i, j, k, w; for i from 1 by 1 to n do a:=0; for j from i by -1 to 0 do k:=j; w:=j-2; while w>0 do k:=k*w; w:=w-2; od; a:=a+k*(-1)^j od; if isprime(abs(a)+1) then print(abs(a)+1); fi; od; end: P(1000);
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CROSSREFS
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Cf. A071828, A130308.
Adjacent sequences: A130306 A130307 A130308 this_sequence A130310 A130311 A130312
Sequence in context: A059785 A087358 A057736 this_sequence A090870 A088542 A075840
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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 21 2007
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