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A152050
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Smallest lower twin prime tp such that p + tp + 1 is prime. p ranges over the prime numbers.
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0
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3, 5, 3, 5, 3, 5, 3, 5, 11, 5, 3, 5, 3, 5, 5, 11, 5, 3, 11, 5, 3, 5, 11, 3, 5, 3, 5, 3, 17, 3, 5, 11, 11, 17, 5, 5, 3, 5, 5, 11, 11, 5, 3, 29, 11, 11, 3, 5, 3, 5, 11, 29, 5, 5, 5, 11, 5, 3, 11, 29, 17, 3, 5, 3, 29, 5, 11, 5, 3, 5, 29, 5, 5, 3, 5, 11, 3, 17, 11, 11, 11, 11, 5, 3, 5, 11, 3, 5, 3, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Conjecture: For all primes p <= n there is always a lower twin prime L less
than n such that p+L+1 is prime.
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EXAMPLE
| 29 is the 9-th odd prime. 29+3+1,29+5+1 are not prime. 29+11+1 is prime, so
a(9) = 11 the smallest lower twin prime satisfying the definition for prime 29.
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PROG
| (PARI) g(n) = ct=0; for(x=2, n, p1=prime(x); for(y=1, n, p2=twinl(y); z=p1+p2+1;
if(isprime(z), ct++; print1(p2", "); break))); ct
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CROSSREFS
| Sequence in context: A175999 A010703 A107489 * A103506 A094929 A096634
Adjacent sequences: A152047 A152048 A152049 * A152051 A152052 A152053
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KEYWORD
| nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)hotmail.com), Nov 21 2008
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