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%I #15 Nov 09 2018 07:33:21
%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,
%T 0,1,0,0,0,1,0,0,0,0,0,0,0,2,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,2,0,0,0,0,
%U 0,0,0,3,0,0,0,0,0,0,0,2,1,0,0,1,0,0,0,1,0,1,0,0,0,0,0,4
%N Number of ways to write n as n = a*b*c*d with 1 < a <= b <= c <= d < n.
%C This sequence is different from A101638.
%C If p is prime, a(p^k) = A026810(k). - _Robert Israel_, Nov 08 2018
%H Robert Israel, <a href="/A321379/b321379.txt">Table of n, a(n) for n = 1..10000</a>
%e 16 = 2*2*2*2. So a(16) = 1.
%e 24 = 2*2*2*3. So a(24) = 1.
%p N:= 100: # for a(1)..a(N)
%p V:= Vector(N):
%p for a from 2 to floor(N^(1/4)) do
%p for b from a to floor((N/a)^(1/3)) do
%p for c from b to floor((N/a/b)^(1/2)) do
%p for d from c to N/(a*b*c) do
%p V[a*b*c*d]:= V[a*b*c*d]+1
%p od od od od:
%p convert(V,list); # _Robert Israel_, Nov 08 2018
%Y Cf. A026810, A122179, A218320.
%K nonn
%O 1,48
%A _Seiichi Manyama_, Nov 08 2018
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