I If (x-a)^2*x^2+76 = (x+a)^4 -(x-a)^4, then
II x(8a^3-a^2 x+10ax^2-x^3)=76, with x={1,2,4,19,38,76},
when {a=1,x=2} is the only solution in the positive integers.
blackjack
flooble's webmaster puzzle