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A077800 List of twin primes {p, p+2}. 39

%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.

%D H. Tronnolone, A tale of two primes, COLAUMS Space, #3, 2013, http://maths.adelaide.edu.au/hayden.tronnolone/publications/A_tale_of_two_primes.pdf

%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&amp;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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Last modified September 30 13:31 EDT 2014. Contains 247425 sequences.