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Search: id:A166339
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| A166339 |
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Numbers n such that Sum(n!/k!),k=0..n is prime. |
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+0
1
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OFFSET
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1,2
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COMMENT
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No further terms up to n=20000. The sequence a[n]=Sum(n!/k!),k=0..n is A000522.
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FORMULA
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n is an index of the sequence a[n]=Sum(n!/k!),k=0..n such that a[n] is prime.
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EXAMPLE
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For n=2, a[2]=5 which is a prime.
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PROGRAM
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(PARI) a=1; for(n=1, 20000, a=n*a+1; if(ispseudoprime(a, 0), print("n="n)));
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CROSSREFS
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Cf. A000522 (corresponding sequence).
Sequence in context: A160299 A125635 A124361 this_sequence A024034 A101722 A004908
Adjacent sequences: A166336 A166337 A166338 this_sequence A166340 A166341 A166342
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KEYWORD
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nonn
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AUTHOR
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Mike Oakes (mikeoakes2(AT)aol.com), Oct 12 2009
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