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A120637
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Primes such that their triple is 2 away from a prime number.
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0
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3, 5, 7, 11, 13, 17, 19, 23, 29, 37, 43, 47, 53, 59, 61, 67, 71, 79, 83, 89, 97, 103, 113, 127, 137, 139, 149, 163, 167, 173, 181, 191, 193, 197, 199, 211, 227, 233, 239, 251, 257, 263, 269, 271, 277, 293, 307, 313, 317, 331, 337, 347, 349, 353, 367, 373, 383
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| This sequence is a variation of the sequence in the reference. However, this sequence should have an infinite number of terms.
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REFERENCES
| R. Crandall and C. Pomerance, Prime Numbers A Computational Perspective, Springer Verlag 2002, p. 49, exercise 1.18.
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EXAMPLE
| 19 is a prime and 19*3 = 57 which is two away from 59 which is prime.
31 is not in the table because 31*3 = 93 which is 2 away from 91 and 95, both not prime.
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MATHEMATICA
| Select[Prime[Range[200]], PrimeQ[3#+2]||PrimeQ[3#-2]&] (* From Harvey P. Dale, Aug 10 2011 *)
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PROG
| (PARI) primepm2(n, k) { 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
| Sequence in context: A002556 A130101 A130057 * A064534 A139758 A060770
Adjacent sequences: A120634 A120635 A120636 * A120638 A120639 A120640
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KEYWORD
| easy,nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Aug 17 2006
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