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%I #21 Feb 08 2022 07:41:44
%S 4,6,9,12,18,21,24,33,39,42,51,54,66,72,81,84,93,114,117,123,138,144,
%T 156,171,177,189,192,207,213,219,222,231,252,276,291,306,318,324,339,
%U 348,357,369,378,396,408,417,429,441,462,471,486,507,513,522,528,546
%N a(n) = A087696(n)/2.
%C "Example 3: Ordinary twins 2a +- 1 for a = 2, 3, 6, 9, 15, . . . have D = 1 and are in class I. For D = 3, the twins 2a +- 3 occur for a = 4, 5, 7, 8, 10"; the latter is this sequence, from p. 3 of Weber. - _Jonathan Vos Post_, Feb 14 2011
%H Vincenzo Librandi, <a href="/A088765/b088765.txt">Table of n, a(n) for n = 1..3100</a>
%H H. J. Weber, <a href="http://arxiv.org/abs/1102.3075">Exceptional Prime Number Twins, Triplets and Multiplets</a>, arXiv:1102.3075 [math.NT], 2011.
%t Select[Range[3, 2000], PrimeQ[# + 5] && PrimeQ[# - 5] &] / 2 (* _Vincenzo Librandi_, May 20 2017 *)
%o (Magma) [n/2: n in [3..2000] |IsPrime(n+5) and IsPrime(n-5)]; // _Vincenzo Librandi_, May 20 2017
%Y Cf. A087696, A040040, A088763, A088767, A088769.
%K nonn
%O 1,1
%A _Ray Chandler_, Oct 26 2003
%E Offset changed from 0 to 1 by _Vincenzo Librandi_, May 21 2017
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