theorem Th49: :: NUMBER13:49

for n, x, y, z, t being positive Nat st x <= y & y <= z holds
( ((n |^ x) + (n |^ y)) + (n |^ z) = n |^ t iff ( ( n = 2 & y = x & z = x + 1 & t = x + 2 ) or ( n = 3 & y = x & z = x & t = x + 1 ) ) )