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A212060 Number of (w,x,y,z) with all terms in {1,...,n} and w=x*y*z-2.

%I A212060 #10 Oct 23 2019 16:44:10
%S A212060 0,0,3,6,15,18,28,34,43,46,64,67,76,85,100,103,121,124,142,151,160,
%T A212060 163,193,199,208,218,236,239,266,269,290,299,308,317,353,356,365,374,
%U A212060 404,407,434,437,455,473,482,485,530,536,554,563,581,584,614,623
%N A212060 Number of (w,x,y,z) with all terms in {1,...,n} and w=x*y*z-2.
%C A212060 For a guide to related sequences, see A211795.
%H A212060 Robert Israel, <a href="/A212060/b212060.txt">Table of n, a(n) for n = 0..10000</a>
%p A212060 N:= 100:
%p A212060 A:= Vector(N):
%p A212060 for x from 1 to N do
%p A212060   for y from 1 to min(N,floor((N+2)/x)) do
%p A212060     for z from max(1,ceil(3/(x*y))) to min(N,floor((N+2)/(x*y))) do
%p A212060   w:=max(x,y,z,x*y*z-2);
%p A212060   A[w]:= A[w]+1;
%p A212060 od od od:
%p A212060 B:= ListTools:-PartialSums(convert(A,list)):
%p A212060 0,op(B); # _Robert Israel_, Oct 23 2019
%t A212060 t = Compile[{{n, _Integer}}, Module[{s = 0},
%t A212060 (Do[If[w == x*y*z - 2, s = s + 1],
%t A212060 {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
%t A212060 Map[t[#] &, Range[0, 60]] (* A212060 *)
%t A212060 (* _Peter J. C. Moses_, Apr 13 2012 *)
%Y A212060 Cf. A211795.
%K A212060 nonn
%O A212060 0,3
%A A212060 _Clark Kimberling_, Apr 30 2012