OFFSET
1,2
COMMENTS
a(6) > 10^17. - Giovanni Resta, Mar 20 2014
m = k^2, where k satisfies k' = (k-1)/2. - Charlie Neder, Mar 08 2019
EXAMPLE
For m = 441 we have that m' = 420, sqrt(441) = 21 and 420 = 441 - 21.
MAPLE
with(numtheory); P:= proc(q) local n, p, x;
for n from 1 to q do x:=n^2;
if x*add(op(2, p)/op(1, p), p=ifactors(x)[2])=n^2-n then print(n^2);
fi; od; end: P(10^9);
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Mar 20 2014
STATUS
approved