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A114265
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Smallest prime p greater than prime(n) such that 2*prime(n) + p is a prime.
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3
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3, 5, 7, 17, 19, 17, 19, 23, 37, 31, 41, 53, 67, 53, 73, 61, 61, 71, 89, 97, 83, 83, 97, 103, 113, 109, 107, 139, 113, 127, 167, 139, 157, 179, 151, 197, 173, 173, 223, 211, 199, 239, 211, 227, 199, 233, 239, 227, 229, 233, 277, 241, 251, 271, 283, 271, 271, 281
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OFFSET
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1,1
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COMMENTS
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Note that p is next prime after prime(n) iff prime(n) is a term in A173971. - Zak Seidov, Feb 11 2015
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LINKS
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EXAMPLE
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n=1: 2*prime[1]+3=2*2+3=7 is prime, so a(1)=3;
n=2: 2*prime[2]+5=2*3+5=11 is prime, so a(2)=5;
...
n=4: 2*prime[4]+3=2*7+3=17 is prime, so a(4)=17.
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MATHEMATICA
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Table[p1 = Prime[n1]; n2 = 1; p2 = Prime[n1 + n2]; While[cp = 2*p1 + p2; ! PrimeQ[cp], n2++; p2 = Prime[n1 + n2]]; p2, {n1, 1, 200}]
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PROG
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(Haskell)
a114265 n = head [p | let (q:qs) = drop (n - 1) a000040_list, p <- qs,
a010051 (2 * q + p) == 1]
(PARI) a(n)=forprime(p=prime(n)+1, , if(isprime(2*prime(n)+p), return(p)))
vector(100, n, a(n)) \\ Derek Orr, Feb 11 2015
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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