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Search: id:A080698
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| A080698 |
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Product of twin-prime-index-primes and their lower bound twin prime. |
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+0
1
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| 15, 55, 341, 1003, 3161, 7339, 16343, 25063, 55247, 62809, 105901, 127991, 190277, 220223, 236597, 325291, 358261, 463487, 512263, 641593, 812327, 1213843, 1293431, 1502399, 1944893, 2351677, 2633803, 2806733, 3050519, 3250847
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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Let p(i) = i-th prime, let twin(n) = (P, Q) be n-th pair of twin primes; sequence gives p(P)*P.
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EXAMPLE
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The 3rd pair of twin primes is twin(3) = (11,13), prime(11) = 31. a(3) = 31*11 = 341
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PROGRAM
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(PARI) twipxpindex(n) = {sr=0; pr=1; for(x=1, n, p1=prime(x); p2=prime(x+1); if((p2-p1)==2, pr=p1*prime(prime(x)); sr+=1.0/pr; print1(pr" ")); ); print(); print(sr) }
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CROSSREFS
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Cf. A057470.
Sequence in context: A119134 A119658 A072745 this_sequence A082235 A104724 A106659
Adjacent sequences: A080695 A080696 A080697 this_sequence A080699 A080700 A080701
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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), Mar 04 2003
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