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 A079111 #5 Jun 13 2017 15:52:55 %S A079111 1,2,3,5,6,7,8,9,11,13,14,15,17,18,19,20,21,23,26,29,30,31,33,35,36, %T A079111 37,39,41,43,44,47,48,50,51,53,54,56,59,61,63,65,67,68,69,71,73,74,75, %U A079111 78,79,81,83,86,89,90,95,96,97,98,99,101,103,105,107,109,111,113,114,116 %N A079111 Numbers n such that 2*n+1 or n itself is prime. %C A079111 Union of A000040 and A005097; complement of A077654. %F A079111 a(n) ~ (n log n)/2. - _Charles R Greathouse IV_, Jun 13 2017 %o A079111 (PARI) is(n)=isprime(n) || isprime(2*n+1) \\ _Charles R Greathouse IV_, Jun 13 2017 %K A079111 nonn %O A079111 1,2 %A A079111 _Reinhard Zumkeller_, Dec 24 2002