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Search: id:A118552
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| A118552 |
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Sum of the twin prime pairs less than 10^n. |
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+0
4
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| 20, 488, 24236, 1726412, 109114568, 7424366648, 545678596592, 41205774636932, 3234489739234676, 260643410442091112, 21446976192435396140, 1795640886305783918948
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The Pari program can compute the first 9 terms in reasonable time. a(10) was computed by the program in the link. This took 13.5 hrs on a p4 2.53 ghz.
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LINKS
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Cino Hilliard, Sum of twin primes less than 10^n.
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EXAMPLE
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(3,5),(5,7) are the two twin prime pairs less than 10. These add up to 20, the
first term in the table.
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PROGRAM
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(PARI) sumtwins(n) = { local(x, j, s, sr, p10x); for(x=1, n, s=0; p10x=10^x; forstep(j=3, 10^x, 2, if(j+2 < p10x & ispseudoprime(j) & ispseudoprime(j+2), s+=j+j+2); ); print1(s", "); ) }
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CROSSREFS
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Sequence in context: A049382 A065412 A000827 this_sequence A092087 A008270 A130186
Adjacent sequences: A118549 A118550 A118551 this_sequence A118553 A118554 A118555
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KEYWORD
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hard,more,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), May 07 2006
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EXTENSIONS
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2 more terms from Giovanni Resta (g.resta(AT)iit.cnr.it), May 08 2006
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