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 A126286 #8 May 20 2015 15:53:31
%S A126286 2,3,2,10,2,21,2,12,6,55,2,78,2,21,10,136,2,171,2,30,14,253,2,60,10,
%T A126286 39,18,406,2,465,2,48,22,85,14,666,2,57,26,820,2,903,2,66,30,1081,2,
%U A126286 168,14,75,34,1378,2,135,22,84,38,1711,2,1830,2,93,42,160,26,2211,2,102,46
%N A126286 a(1) = 2, a(n) = n * LeastPrimeFactor(n+1) / LeastPrimeFactor(n).
%H A126286 Ivan Neretin, <a href="/A126286/b126286.txt">Table of n, a(n) for n = 1..10000</a>
%F A126286 a(n) = A032742(n)*A020639(n+1), for n>1. - _Ivan Neretin_, May 20 2015
%e A126286 a(6) = (6 / LeastPrimeFactor(6)) * LeastPrimeFactor(7) = 21.
%t A126286 a[1] := 2; a[n_] := n*FactorInteger[n + 1][[1, 1]]/FactorInteger[n][[1, 1]]; Table[a[n], {n, 69}] (* _Ivan Neretin_, May 20 2015 *)
%o A126286 (PARI) a(n) = if (n==1, 2, n*factor(n+1)[1, 1]/factor(n)[1, 1]); \\ _Michel Marcus_, Aug 14 2013
%Y A126286 Cf. A126287, A126288, A126289, A020639.
%K A126286 easy,nonn
%O A126286 1,1
%A A126286 _Lior Manor_, Dec 25 2006