cp's OEIS Frontend

A147778 Positive integers of the form u*v*(u^2 - v^2) where u, v are coprime integers.

%I A147778 #10 Jul 25 2017 02:41:44
%S A147778 6,24,30,60,84,120,180,210,240,330,336,504,546,630,720,840,924,990,
%T A147778 1224,1320,1386,1560,1710,1716,2016,2184,2310,2340,2520,2574,2730,
%U A147778 3036,3360,3570,3696,3900,3960,4080,4290,4620,4896,4914,5016,5280,5544,5610,5814
%N A147778 Positive integers of the form u*v*(u^2 - v^2) where u, v are coprime integers.
%C A147778 Terms with even u or v form A024365. Squarefree terms form A147779.
%H A147778 Robert Israel, <a href="/A147778/b147778.txt">Table of n, a(n) for n = 1..10000</a>
%p A147778 N:= 10^5:
%p A147778 A:= {}:
%p A147778 for v from 1 to floor((N/2)^(1/3)) do
%p A147778    for u from v+1 do
%p A147778       if igcd(u,v) = 1 then
%p A147778         t:= u*v*(u^2-v^2);
%p A147778         if t > N then break fi;
%p A147778         A:= A union {t};
%p A147778       fi
%p A147778     od
%p A147778 od:
%p A147778 A;
%p A147778 # if using Maple 11 or earlier, uncomment the next line
%p A147778 # sort(convert(A,list)); # _Robert Israel_, Apr 06 2015
%Y A147778 Subsequence of: A003273, A009112, A073120.
%K A147778 nonn
%O A147778 1,1
%A A147778 _Max Alekseyev_, Nov 12 2008