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 A126289 #13 Oct 07 2020 05:38:54
%S A126289 1,1,2,6,2,10,3,28,6,6,5,44,3,26,21,40,2,102,3,76,15,14,11,184,15,10,
%T A126289 117,12,7,174,5,496,6,22,85,84,3,74,57,104,5,246,7,172,99,10,23,752,
%U A126289 21,70,15,68,13,954,15,88,21,38,29,708,5,122,279,224,10,78,11,268,51,230,7
%N A126289 a(1) = 1, a(2) = 1, a(n) = n * LargestPrimeFactor(n-1) / LargestPrimeFactor(n).
%H A126289 Ivan Neretin, <a href="/A126289/b126289.txt">Table of n, a(n) for n = 1..10000</a>
%F A126289 a(n) = A006530(n-1)*A052126(n) for n>2. - _Michel Marcus_, May 20 2015
%e A126289 a(6) = 6 * LargestPrimeFactor(5) / LargestPrimeFactor(6) = 6 * 5 / 3 = 10
%t A126289 a[1] := 1; a[2] := 1; a[n_] := n*FactorInteger[n - 1][[-1, 1]]/FactorInteger[n][[-1, 1]]; Table[a[n], {n, 71}] (* _Ivan Neretin_, May 20 2015 *)
%o A126289 (PARI) gpf(n) = vecmax(factor(n)[,1]); \\ A006530
%o A126289 a(n) = if (n<=2, 1, n*gpf(n-1)/gpf(n)); \\ _Michel Marcus_, Oct 07 2020
%Y A126289 Cf. A126286, A126287, A126288, A006530.
%K A126289 easy,nonn
%O A126289 1,3
%A A126289 _Lior Manor_, Dec 25 2006