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 A272476 #19 Sep 08 2022 08:46:16
%S A272476 3,5,2,3,11,5,15,7,19,21,23,11,27,13,31,33,35,17,39,19,43,45,47,23,51,
%T A272476 53,55,57,59,29,63,31,67,69,71,73,75,37,79,81,83,41,87,43,91,93,95,47,
%U A272476 99,101,103,105,107,53,111,113,115,117,119,59,123,61,127
%N A272476 a(n) = n if n is prime, a(n) = 2*n+3 otherwise.
%C A272476 Prime numbers repeated: 3, 5, 11, 19, 23, 31, 43, 47, 53, 59, 67, 71, ..., that is A065091 without A089531.
%H A272476 Vincenzo Librandi, <a href="/A272476/b272476.txt">Table of n, a(n) for n = 0..1000</a>
%t A272476 Table[If[PrimeQ[n], n, 2 n + 3], {n, 0, 150}]
%o A272476 (Magma) [IsPrime(n) select n else 2*n+3: n in [0..80]];
%Y A272476 Cf. A000040, A018252.
%Y A272476 Cf. A061397, A191558.
%K A272476 nonn,easy
%O A272476 0,1
%A A272476 _Vincenzo Librandi_, May 02 2016