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Search: id:A120638
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| A120638 |
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Primes such that their triple is not 2 away from a prime number. |
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+0
1
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| 2, 31, 41, 73, 101, 107, 109, 131, 151, 157, 179, 223, 229, 241, 281, 283, 311, 359, 379, 389, 421, 449, 463, 509, 521, 547, 563, 571, 599, 613, 617, 619, 631, 641, 647, 653, 661, 683, 691, 701, 719, 733, 739, 743, 773, 787, 809, 811, 821, 827, 829, 839, 857
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This sequence is a variation of the sequence in the reference. However, this sequence should have an infinite number of terms. k=2 in the PARI code.
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REFERENCES
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R. Crandall and C. Pomerance, Prime Numbers A Computational Perspective, Springer Verlag 2002, p. 49, exercise 1.18.
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EXAMPLE
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31*3 = 93 which is two away from 91 and 95 both not prime.
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PROGRAM
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(PARI) primepm3(n, k) = =number of iterations, k = factor { local(x, p1, p2, f1, f2, r); if(k%2, r=2, r=1); for(x=1, n, p1=prime(x); p2=prime(x+1); if(!isprime(p1*k+r)&!isprime(p1*k-r), print1(p1", ") ) ) }
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CROSSREFS
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Sequence in context: A020896 A042153 A102630 this_sequence A101017 A129900 A105757
Adjacent sequences: A120635 A120636 A120637 this_sequence A120639 A120640 A120641
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Aug 17 2006
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