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A136020
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Smallest prime of the form (2*n+1)*prime(k)-2*n, any k.
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57
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7, 11, 29, 19, 23, 53, 31, 103, 191, 43, 47, 101, 109, 59, 311, 67, 71, 149, 79, 83, 173, 181, 283, 197, 103, 107, 331, 229, 709, 367, 127, 131, 269, 139, 853, 293, 151, 463, 317, 163, 167, 1021, 349, 179, 547, 373, 191, 389, 199, 607, 619, 211, 643, 1091, 223
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The associated prime(k) are in A136019.
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LINKS
| Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
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EXAMPLE
| a(1)=7 because 7 is smallest prime p such that (p+2)/3 is prime
a(2)=11 because 11 is smallest prime p such that (p+4)/5 is prime
a(3)=29 because 29 is smallest prime p such that (p+6)/7 is prime
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MATHEMATICA
| a = {}; Do[k = 1; While[ !PrimeQ[(Prime[k] + 2n)/(2n + 1)], k++ ]; AppendTo[a, Prime[k]], {n, 1, 100}]; a
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PROG
| (PARI) a(n)=my(t); n+=n; forprime(p=2, default(primelimit), if(isprime(t=(n+1)*p-n), return(t))) \\ Charles R Greathouse IV, Feb 13 2011
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CROSSREFS
| Cf. A136019, A136026, A136027.
Sequence in context: A045736 A158807 A067006 * A076304 A122560 A136338
Adjacent sequences: A136017 A136018 A136019 * A136021 A136022 A136023
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KEYWORD
| nonn,easy
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Dec 10 2007
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EXTENSIONS
| Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 17 2009
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