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 A054902 #14 Dec 19 2013 10:56:21 %S A054902 65,170,209,1394,3393,4407,4556,11009,13736,27674,38009,38845,47402, %T A054902 76994,157994,162393,184740,186686,209294,680609,825359,954521, %U A054902 1243574,2205209,3515609,4347209,5968502,6539102,6916241,8165294,10352294,10595009,10786814 %N A054902 Composite numbers n such that sigma(n)+12 = sigma(n+12). %H A054902 Donovan Johnson, <a href="/A054902/b054902.txt">Table of n, a(n) for n = 1..500</a> %e A054902 n = 65, sigma(65)+12 = 84+12 = 96 = sigma(65+12) = sigma(77). %e A054902 n = 11009, sigma(11009)+12 = 11220+12 = 11232 = sigma(11009+12) = sigma(11021). %o A054902 (PARI) isok(n) = !isprime(n) && ((sigma(n)+12) == sigma(n+12)); \\ _Michel Marcus_, Dec 18 2013 %Y A054902 Complement of A046133 with respect to A015917. %Y A054902 Cf. A015913-A015917, A023200, A023203, A046133, A001359, A054799. %K A054902 nonn %O A054902 1,1 %A A054902 _Labos Elemer_, May 23 2000 %E A054902 More terms from _Jud McCranie_, May 24 2000 %E A054902 Three more terms from _Michel Marcus_, Dec 18 2013