cp's OEIS Frontend

A060275 At least two ordered triples of positive numbers have sum n and equal products.

%I A060275 #15 Nov 07 2022 07:41:11
%S A060275 13,14,16,17,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,
%T A060275 38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,
%U A060275 61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83
%N A060275 At least two ordered triples of positive numbers have sum n and equal products.
%C A060275 Any two such triples are disjoint.
%C A060275 Complement appears to be {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 18}. - _Robert Israel_, Feb 10 2015
%e A060275 13=6+6+1=9+2+2, 6*6*1=9*2*2, so 13 is in the sequence.
%p A060275 N:= 100: # to get all entries <= N
%p A060275 for i from 1 to N do R[i]:= {} od:
%p A060275 A:= {}:
%p A060275 for a from 1 to floor(N/3) do
%p A060275   for b from a to floor((N-a)/2) do
%p A060275     for c from b to N-a-b do
%p A060275        p:= a*b*c;
%p A060275        s:= a+b+c;
%p A060275        if member(p,R[s]) then A:= A union {s}
%p A060275        else R[s]:= R[s] union {p}
%p A060275        fi;
%p A060275 od od od:
%p A060275 A;
%p A060275 # if using Maple 11 or earlier, uncomment the next line
%p A060275 # sort(convert(A,list));  # _Robert Israel_, Feb 10 2015
%K A060275 easy,nonn
%O A060275 1,1
%A A060275 _Naohiro Nomoto_, Mar 23 2001
%E A060275 Name changed by _Robert Israel_, Feb 12 2015