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A215913
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Primes of the form 2*!n-1.
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0
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OFFSET
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0,1
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COMMENTS
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!n is a subfactorial number (A000166). The corresponding n are {3, 4, 12, 13, 97,...}.
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LINKS
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Table of n, a(n) for n=0..3.
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EXAMPLE
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The prime 17 = 2* !4 - 1 = 2*9 -1 is in the sequence.
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MAPLE
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with(numtheory): f:=n->sum(n!*(((-1)^k)*1/k!), k=0..n):for n from 1 to 150 do: if type(2*f(n)-1, prime) = true then printf(`%d, `, 2*f(n)-1):else fi:od:
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MATHEMATICA
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a={}; Do[p= 2* Subfactorial[n]-1; If[PrimeQ[p], AppendTo[a, p]], {n, 0, 800}]; Print[a];
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CROSSREFS
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Cf. A006882, A215912.
Sequence in context: A351590 A175984 A051710 * A162713 A161473 A208493
Adjacent sequences: A215910 A215911 A215912 * A215914 A215915 A215916
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KEYWORD
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nonn
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AUTHOR
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Michel Lagneau, Aug 26 2012
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STATUS
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approved
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