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Search: id:A089629
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| A089629 |
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Smallest member of a pair of consecutive twin prime pairs that have one prime between them. |
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+0
2
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| 17, 29, 59, 227, 269, 617, 1031, 1277, 1289, 1301, 1607, 1667, 1697, 2087, 2129, 2309, 2711, 2789, 3257, 3527, 3539, 3557, 3917, 4019, 4241, 4517, 4637, 4787, 5477, 5501, 5639, 6551, 7307, 8819, 8837, 8999, 9011, 10037, 10067, 10271, 10499, 12041, 13679
(list; graph; listen)
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OFFSET
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3,1
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COMMENT
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Run the pari script savetwins(100000) or so to build the twinprime array of lower bounds before you run the main script.
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EXAMPLE
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Twin prime pairs 17,19 and 29,31 have only the prime 23 between them.
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PROGRAM
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(PARI) pbetweentw(n, p) = \p is the number of primes between { forstep(x1=1, n, 1, c=0; t1 = twin[x1]; t2 = twin[x1+1]; for(y=t1+4, t2-1, if(isprime(y), c++) ); if(c==p, print1(t1", ")) ) } \ build a twin prime table of lower bounds savetwins(n) = { twin = vector(n); c=1; forprime(x=3, n*10, if(isprime(x+2), twin[c]=x; c++; ) ) }
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CROSSREFS
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Sequence in context: A110573 A139840 A090796 this_sequence A007349 A154616 A069755
Adjacent sequences: A089626 A089627 A089628 this_sequence A089630 A089631 A089632
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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), Jan 01 2004
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