%I #64 Jun 11 2020 16:51:50
%S 1,2,3,4,4,6,6,8,8,10,10,12,12,12,12,12,12,18,18,20,20,20,20,24,24,24,
%T 24,24,24,30,30,30,30,30,30,36,36,36,36,36,36,36,36,36,36,36,36,48,48,
%U 48,48,48,48,48,48,48,48,48,48,60,60,60,60,60,60,60,60,60,60,60,60,72
%N a(n) is the largest index in [n] that maximizes tau.
%H Peter Andrew, <a href="/A329004/b329004.txt">Table of n, a(n) for n = 1..20000</a>
%F a(n) = n <=> n in { A067128 }. - _Alois P. Heinz_, Jun 11 2020
%p a:= proc(n) option remember; uses numtheory; `if`(n=1, 1,
%p (t-> `if`(tau(n)<tau(t), t, n))(a(n-1)))
%p end:
%p seq(a(n), n=1..100); # _Alois P. Heinz_, Jun 11 2020
%t dmax = 0; nmax = 1; seq = {}; Do[If[(d = DivisorSigma[0, n]) >= dmax, dmax = d; nmax = n]; AppendTo[seq, nmax], {n, 1, 72}]; seq (* _Amiram Eldar_, Jun 11 2020 *)
%o (Haskell) a329004 = map fst $ scanl1 (\x y -> maximumBy (comparing snd) [x,y]) $ zip [1..] a000005
%Y Cf. A000005, A067128.
%K nonn
%O 1,2
%A _Peter Andrew_, Jun 10 2020