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Search: id:A147853
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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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+0
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
(list; graph; listen)
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OFFSET
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2,1
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COMMENT
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Improved description from T. D. Noe (noe(AT)sspectra.com).
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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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PROGRAM
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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: A072055 A164316 A107448 this_sequence A111226 A084197 A073681
Adjacent sequences: A147850 A147851 A147852 this_sequence A147854 A147855 A147856
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KEYWORD
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easy,nonn
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AUTHOR
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Bill R McEachen (bmceache(AT)centralsan.org), Nov 15 2008
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