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A087575
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Smallest prime p such that 2+p^n is a prime, or 0 if no such prime exists.
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0
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3, 3, 3, 3, 11, 0, 53, 3, 11, 3, 23, 0, 71, 3, 3, 0, 5, 0, 521, 0, 1847, 0, 41, 3, 71, 3, 59, 0, 191, 0, 71, 0, 827, 0, 761, 3, 1721, 0, 23, 0, 197, 0, 1229, 0, 59, 0, 1493, 0, 101, 0, 389, 0, 2381, 0, 3023, 0, 4691, 0, 6263, 0, 9719, 0, 3, 0, 2207, 0, 983, 0, 6701, 0, 239, 0, 347
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(2)=a(3)=a(4)=3, as 3^2 + 2, 3^3 + 2, 3^4 + 2 are all prime.
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PROG
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(PARI) for(j=1, 50, forprime (i=1, 50000, if(isprime(i^j+2), print1(i, ", "); break())))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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More terms from Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 14 2004
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STATUS
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approved
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