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A071828
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Primes of the form Sum_{i=1..k} (-1)^(k-i)*i!.
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9
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OFFSET
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1,1
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LINKS
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FORMULA
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MATHEMATICA
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l = Abs@Accumulate[(-1)^#*#! & /@ Range@99]; l[[Flatten@Position[l, _?PrimeQ]]] (* Hans Rudolf Widmer, Feb 27 2023 *)
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PROG
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(PARI) for(n=1, 120, if(isprime(abs(sum(i=1, n, (-1)^i*i!)))==1, print1(abs(sum(i=1, n, (-1)^i*i!)), ", ")))
(PARI) v=[]; for(n=1, 1000, if(ispseudoprime(t=abs(sum(i=1, n, (-1)^i*i!))), v=concat(v, t))); v \\ Charles R Greathouse IV, Feb 14 2011
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CROSSREFS
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KEYWORD
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nonn,fini
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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