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Number of distinct products i*j*k with 1 <= i < j <= k <= n.
0

%I #10 Mar 06 2020 01:01:51

%S 0,0,2,7,16,24,40,56,77,96,137,158,214,249,284,322,418,464,583,645,

%T 708,774,946,1007,1125,1220,1330,1420,1685,1768,2069,2203,2346,2492,

%U 2658,2750,3166,3362,3553,3675,4183,4344,4909,5129,5327,5575,6252,6432,6849

%N Number of distinct products i*j*k with 1 <= i < j <= k <= n.

%o (PARI) for(n=1,100,s=Set();for(i=1,n-2,for(j=i+1,n-1,for(k=j,n,p=i*j*k;if(!setsearch(s,p),s=setunion(s,Set(p))))));print1(length(s),",")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 06 2006

%Y Cf. A027430, A100435.

%K nonn

%O 1,3

%A _N. J. A. Sloane_

%E Better definition and more terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 06 2006