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Search: id:A062391
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| A062391 |
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a(1) = 3, a(2) = 5; a(n+1) = smallest prime number > a(n) such that the sum of any three consecutive terms is a prime. |
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+0
13
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| 3, 5, 11, 13, 17, 23, 31, 43, 53, 61, 67, 71, 73, 79, 89, 101, 103, 107, 127, 139, 167, 173, 181, 193, 197, 211, 223, 227, 233, 241, 269, 277, 281, 349, 353, 359, 379, 433, 467, 499, 521, 523, 557, 577, 587, 613, 631, 743, 757, 769, 821, 827, 829, 883, 947
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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What is the longest string of consecutive primes? A derived sequence could be the start of the first occurrence of a string of n consecutive primes in this sequence.
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LINKS
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Zak Seidov, Table of n, a(n) for n = 1..1000.
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EXAMPLE
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After 43, the next term is 53, since 31+43+47=121 is not prime and 31+43+53=127 is prime.
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MATHEMATICA
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a=3; b=5; lst={a, b}; Do[c=a+b+n; If[PrimeQ[c]&&n>b&&PrimeQ[n], AppendTo[lst, n]; a=b; b=n], {n, 0, 8!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 17 2008]
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PROGRAM
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(PARI) { n=a1=0; forprime (p=3, 5*10^5, if (p<6 || isprime(p + s), write("b062391.txt", n++, " ", p); s=a1 + p; a1=p; if (n==1000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 07 2009]
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CROSSREFS
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Cf. A072536, A072537, A000040.
Sequence in context: A130097 A020612 A072539 this_sequence A038951 A154500 A020578
Adjacent sequences: A062388 A062389 A062390 this_sequence A062392 A062393 A062394
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KEYWORD
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nonn,easy
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 27 2001
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EXTENSIONS
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Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 02 2001
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