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A283563
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Numbers n such that A112368(n) = Sum_{i=0..n} 2^i*i! is prime.
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2
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OFFSET
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1,2
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COMMENTS
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All the terms of A112368 starting from a(72) are divisible by 73.
The first 9 associated primes are 3, 11, 59, 443, 4283, 50363, 85662309563, 1726380042510080613563, 4824162806180387282426469563. The 10th and last term is about 2.022... * 10^123.
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LINKS
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EXAMPLE
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1 is in this sequence because 2^0*0! + 2^1*1! = 3 is prime.
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MATHEMATICA
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A112368[n_] := Sum[2^i*i!, {i, 0, n}]; Select[Range[0, 1000], PrimeQ[A112368[#]] &]
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PROG
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(PARI) isok(n) = isprime(sum(i=0, n, 2^i*i!)); \\ Michel Marcus, Mar 11 2017
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CROSSREFS
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KEYWORD
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nonn,fini,full
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AUTHOR
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STATUS
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approved
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