This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A181938 #14 Aug 03 2014 14:01:26 %S A181938 7,13,19,43,97,103,109,127,139,181,193,229,241,283,307,313,349,397, %T A181938 409,421,457,463,487,499,643,691,709,769,787,811,823,829,853,859,877, %U A181938 883,907,919,937,967,1021,1051,1093,1153,1171,1279,1303,1423,1429,1447,1483 %N A181938 Isolated primes = 1 mod 6: sandwiched by primes = 5 mod 6. %C A181938 Primes p(m) = 1 mod 6 such that both p(m-1) and p(m+1) are congruent to 5 mod 6. %C A181938 Corresponding indices m are 4, 6, 8, 14, 25, 27, 29, 31 (A181978). %C A181938 Note that values of d = p(m+1) - p(m-1) are multiples of 6. %H A181938 Harvey P. Dale, <a href="/A181938/b181938.txt">Table of n, a(n) for n = 1..1000</a> %e A181938 7 = p(4) = 1 mod 6 and both p(3) = 5 and p(5) = 11 are congruent to 5 mod 6, %e A181938 13 = p(6) = 1 mod 6 and both p(5) = 11 and p(7) = 17 are congruent to 5 mod 6, %e A181938 43 = p(14) = 1 mod 6 and both p(13) = 41 and p(15) = 47 are congruent to 5 mod 6. %t A181938 Select[Prime[Range[2, 300]], Mod[#, 6] == 1 && Mod[NextPrime[#, -1], 6] == 5 && Mod[NextPrime[#, 1], 6] == 5 &] (* _T. D. Noe_, Apr 04 2012 *) %t A181938 Transpose[Select[Partition[Prime[Range[250]],3,1],Mod[#[[1]],6] == Mod[#[[3]],6] == 5&&Mod[#[[2]],6]==1&]][[2]] (* _Harvey P. Dale_, Sep 17 2012 *) %Y A181938 Cf. A002476, A039704, A055625, A181978, A210248. %K A181938 nonn %O A181938 1,1 %A A181938 _Zak Seidov_, Apr 03 2012