%I #11 Sep 08 2020 05:30:12
%S 2,3,2,10,3,14,2,12,15,22,3,52,7,10,6,136,3,114,5,28,33,46,3,40,65,6,
%T 63,116,5,186,2,176,51,14,15,444,19,26,15,328,7,258,11,20,207,94,3,
%U 112,35,170,39,212,3,198,35,152,87,118,5,732,31,14,18,416,55,402,17,92,21,710
%N a(1) = 2, a(n) = n * LargestPrimeFactor(n+1) / LargestPrimeFactor(n).
%H Ivan Neretin, <a href="/A126288/b126288.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A006530(n+1)*A052126(n) for n>1. - _Michel Marcus_, May 20 2015
%e a(6) = 6 * LargestPrimeFactor(7) / LargestPrimeFactor(6) = 6 * 7 / 3 = 14
%t a[1] := 2; a[n_] := n*FactorInteger[n + 1][[-1, 1]]/FactorInteger[n][[-1, 1]]; Table[a[n], {n, 70}] (* _Ivan Neretin_, May 20 2015 *)
%o (PARI) gpf(n) = vecmax(factor(n)[,1]);
%o a(n) = if (n==1, 2, n*gpf(n+1)/gpf(n)); \\ _Michel Marcus_, Sep 08 2020
%Y Cf. A126286, A126287, A126289, A006530.
%K easy,nonn
%O 1,1
%A _Lior Manor_, Dec 25 2006