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%I #20 Jun 07 2019 03:03:16
%S 1,2,2,3,4,4,4,6,6,6,8,8,9,10,12,12,12,12,12,12,16,16,18,20,20,24,24,
%T 24,24,24,24,24,24,24,30,32,32,36,36,40,40,48,48,48,48,48,48,48,48,60,
%U 64,64,72,72,72,80,80,84,90,96,96,96,96,96,96,96,96,96,100,108,120,120,120,128,128,144,144,144,144,144,160
%N Number of divisors of A067128(n).
%C Is a(n + 1) / a(n) ~ 1 for large n?
%C Every term in this sequence also appears in A002183, where every element of this sequence occurs exactly once.
%C In A067128 it is asked if A034287 = A067128. If that is the case then this sequence is also the number of divisors of A034287.
%H Amiram Eldar, <a href="/A273353/b273353.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A000005(A067128(n)).
%t s = {}; dmax = 0; Do[d = DivisorSigma[0, n]; If[d >= dmax, AppendTo[s, d]; dmax = d], {n, 1, 10^6}]; s (* _Amiram Eldar_, Jun 07 2019 *)
%o (PARI) is_a067128(n) = my(nd=numdiv(n)); for(k=1, n-1, if(numdiv(k) > nd, return(0))); return(1)
%o for(n=1, 50000, if(is_a067128(n), print1(numdiv(n), ", "))) \\ _Felix Fröhlich_, May 24 2016
%Y Cf. A000005, A002182, A002183, A034287, A067128.
%K nonn
%O 1,2
%A _David A. Corneth_, May 20 2016
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