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 A143545 #12 Feb 16 2017 18:00:25 %S A143545 1,4,6,4,10,6,14,8,9,10,22,12,26,14,15,16,34,18,38,20,21,22,46,24,25, %T A143545 26,27,28,58,30,62,32,33,34,35,36,74,38,39,40,82,42,86,44,45,46,94,48, %U A143545 49,50,51,52,106,54,55,56,57,58,118,60,122,62,63,64,65,66,134,68,69,70,142 %N A143545 a(n) = n unless n is a prime, in which case a(n) = 2n. %H A143545 N. J. A. Sloane, <a href="/A143545/b143545.txt">Table of n, a(n) for n = 1..10000</a> %F A143545 a(n) = n + A061397(n), where A061397 = (0, 2, 3, 0, 5, 0, 7,...). %F A143545 Equals row sums of triangle A143544. %F A143545 a(n)=A066560(n), n>1. [From _R. J. Mathar_, Sep 05 2008] %e A143545 a(3) = 6 = 2*3 since 3 is prime. %e A143545 a(4) = 4 since 4 is a nonprime. %Y A143545 Cf. A066560, A143544, A061397. %Y A143545 See A282028 for another version. %K A143545 nonn %O A143545 1,2 %A A143545 _Gary W. Adamson_, Aug 23 2008 %E A143545 Extended beyond a(14) by _R. J. Mathar_, Sep 05 2008