%I A000355
%S A000355 3,11,23,29,83,89,131,191,251,431,443,491,509,683,743,809,911,1031,1049,
%T A000355 1103,1223,1229,1289,1409,1451,1511,1583,1811,1889,1931,2003,2063,2069,
%U A000355 2129,2351,2543,2549,2903,2963,2969,3023,3329,3389,3449,3491,3623,3803
%N A000355 Primes == 3, 9, 11 (mod 20) such that 2p+1 is also prime.
%C A000355 a(n) = (A000353(n)-1)/2; [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Feb 10 2009]
%D A000355 R. A. J. Matthews, Maximally periodic reciprocals, Bull. Instititute 
               of Mathematics and Its Applications, vol. 28, p. 147-148, 1992.
%H A000355 R. Zumkeller, <a href="b000355.txt">Table of n, a(n) for n = 1..1000</
               a> [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 
               10 2009]
%Y A000355 Subset of A005384.
%Y A000355 Sequence in context: A087078 A141226 A049491 this_sequence A163769 A100860 
               A018630
%Y A000355 Adjacent sequences: A000352 A000353 A000354 this_sequence A000356 A000357 
               A000358
%K A000355 nonn
%O A000355 1,1
%A A000355 R. A. J. Matthews [ 100265.3005(AT)compuserve.com ]
%E A000355 More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               Feb 10 2009