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%I #18 Apr 07 2015 10:50:20
%S 2,6,27,170,1019,6945,50811,381332,2984194,23988173,196963369,
%T 1646209172,13964079652,119945656793,1041428920639,9126986454994,
%U 80644643655861,717727049224277
%N Number of n-digit twin prime pairs.
%D Jean-Marie De Koninck, Armel Mercier: 1001 Problems in Classical Number Theory, American Mathematical Society, 2007 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 23 2010
%D Paulo Ribenboim: The New Book of Prime Number Records (3. Auflage), Springer-Verlag Berlin, 1996 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 23 2010
%H Anonymous, <a href="http://www.mathematical.com/twindex2to1b.htm">Twin Prime Index(1 through 394000000)</a>
%H X. Gourdon & P. Sebah, <a href="http://numbers.computation.free.fr/Constants/Primes/primeonline.html">Online computation of the first primes and twin primes up to 50000</a>
%H Tomás Oliveira e Silva, <a href="http://sweet.ua.pt/tos/primes.html">Tables of values of pi(x) and of pi2(x)</a>
%F a(n) = A007508(n) - A007508(n-1) [From Max Alekseyev, Jun 16 2011]
%e n=1: a(1)=2 pairs: (3,5), (5,7).
%e n=2: a(2)=6 pairs: (11,13), (17,19), (29,31), (41,43), (59,61), (71,73).
%Y Cf. A007508.
%K hard,more,nonn,base
%O 1,1
%A _Lekraj Beedassy_, May 06 2002
%E a(6) corrected by _Harvey P. Dale_, Sep 02 2008
%E a(9) corrected and a(15)-a(18) from _Donovan Johnson_, Apr 25 2010
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