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 A086519 #5 Dec 05 2013 19:56:19 %S A086519 3,7,19,43,31,103,151,67,79,127,199,163,139,223,331,211,271,283,379, %T A086519 367,307,439,487,607,547,499,643,571,523,619,463,631,691,727,739,883, %U A086519 823,751,787,859,907,811,1063,919,1123,1051,967,1171,1087,991,1471,1291 %N A086519 a(n) is the least prime not already used such that (a(n)+a(n-1))/2 is prime. %C A086519 Second term onwards every prime == 1 (mod 6). Conjecture: every prime of the type 6k+1 is a member. %C A086519 After the first term, every member = 7 (mod 12). Conjecture: every prime of the form 12k+7 is a member. - _David Wasserman_, Mar 11 2005 %Y A086519 Cf. A086522. %K A086519 nonn %O A086519 0,1 %A A086519 _Amarnath Murthy_, Jul 30 2003 %E A086519 More terms from _David Wasserman_, Mar 11 2005