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A147853
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Least prime p such that there is a prime q with (p+q)/2=A002110(n), the n-th primorial.
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1
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5, 7, 11, 17, 19, 19, 29, 37, 37, 37, 73, 47, 59, 71, 97, 79, 79, 101, 97, 137, 227, 137, 109, 127, 151, 127, 151, 151, 179, 227, 431, 139, 211, 223, 337, 181, 251, 257, 313, 227, 257, 227, 263, 491, 307, 241, 409, 263, 277
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OFFSET
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2,1
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COMMENTS
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If q>10^22 then q is a probable prime. - Pierre CAMI, Jan 07 2014
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LINKS
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Pierre CAMI, Table of n, a(n) for n = 2..1376
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EXAMPLE
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For primorial=30, (p,q)=(7,53) as 7+53=2*30.
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PROG
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(PARI) ospp(N)= { i=4; while(1, Q=2*N-prime(i); if( ispseudoprime(2*N-prime(i)), print(N, ", ", prime(i) ); return(1) ); i++ ); \end WHILE }
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CROSSREFS
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Cf. A002110, A147517
Sequence in context: A314300 A189320 A107448 * A111226 A168224 A084197
Adjacent sequences: A147850 A147851 A147852 * A147854 A147855 A147856
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KEYWORD
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easy,nonn
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AUTHOR
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Bill McEachen, Nov 15 2008
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EXTENSIONS
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Improved description from T. D. Noe
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STATUS
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approved
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