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%I
%S 3,5,5,7,11,13,17,19,29,31,41,43,59,61,71,73,101,103,107,109,137,139,
%T 149,151,179,181,191,193,197,199,227,229,239,241,269,271,281,283,311,
%U 313,347,349,419,421,431,433,461,463,521,523,569,571,599,601,617,619
%N List of twin primes {p, p+2}.
%C Union (with repetition) of A001359 and A006512.
%D M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 870.
%H Vincenzo Librandi, <a href="/A077800/b077800.txt">Table of n, a(n) for n = 1..1000</a>
%H M. Abramowitz and I. A. Stegun, eds., <a href="http://www.nrbook.com/abramowitz_and_stegun/">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
%H J. P. Delahaye, <a href="http://tr.voila.fr/ano?anolg=65544&anourl=http://www.pour-la-science.com/numeros/pls-260/logique.htm">Twin Primes:Enemy Brothers?</a>
%H J. C. Evard, <a href="http://www.math.utoledo.edu/~jevard/Page012.htm">Twin primes and their applications</a>
%H Wikipedia, <a href="http://www.wikipedia.org/wiki/Twin_prime">Twin prime</a>
%H <a href="/index/Pri#gaps">Index entries for primes, gaps between</a>
%t Sort[ Join[ Select[ Prime[ Range[ 115]], PrimeQ[ # - 2] &], Select[ Prime[ Range[ 115]], PrimeQ[ # + 2] &]]] (from _Robert G. Wilson v_, Jun 09 2005)
%t Select[ Partition[ Prime@ Range@ 115, 2, 1], #[[1]] + 2 == #[[2]] &] // Flatten
%t Flatten[Select[{#, # + 2} & /@Prime[Range[1000]], PrimeQ[Last[#]]&]] (* _Vincenzo Librandi_, Nov 01 2012 *)
%o (Haskell)
%o a077800 n = a077800_list !! (n-1)
%o a077800_list = concat $ zipWith (\p q -> if p == q+2 then [q,p] else [])
%o (tail a000040_list) a000040_list
%o -- _Reinhard Zumkeller_, Nov 27 2011
%o (PARI) p=2;forprime(q=3,1e3,if(q-p==2,print1(p", "q", "));p=q) \\ _Charles R Greathouse IV_, Mar 22 2013
%Y Cf. A070076, A095958. See A001097 for another version.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_, Dec 03, 2002
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