A102534 - OEIS

%I #9 Dec 16 2024 02:09:05

%S 0,1,4,10,19,33,49,70,96,127,161,201,238,287,337,390,449,519,586,662,

%T 741,818,902,997,1095,1194,1299,1410,1518,1651,1778,1908,2054,2186,

%U 2332,2493,2636,2793,2955,3128,3300,3481,3660,3840,4050,4252,4443,4665,4871

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

%H Robert Israel, <a href="/A102534/b102534.txt">Table of n, a(n) for n = 1..2000</a>

%p F:= proc(n) local i,j;

%p       {seq(seq(i*j + (i+j)*n, i=1..j),j=1..n-1)}

%p end proc:

%p R:= NULL:

%p S:= {}:

%p for n from 1 to 100 do

%p   S:= S union F(n);

%p   R:= R,nops(S);

%p od:

%p R; # _Robert Israel_, Dec 15 2024

%t f[n_] := Length[ Union[ Flatten[ Table[i*j + j*k + k*i, {i, n}, {j, i, n}, {k, j + 1, n}]]]]; Table[ f[n], {n, 48}] (* _Robert G. Wilson v_, Jan 13 2005 *)

%Y Cf. A100439, A100440, A102533.

%K nonn

%O 1,3

%A _Robert G. Wilson v_, Jan 13 2005