Three numbers a, b and c are a Pythagorean triple if a 2+b 2=c 2 . The triangular numbers are:
(1x2)/2, (2x3)/2, (3x4)/2, (4x5)/2, ...
Show that 8778, 10296 and 13530 are three triangular numbers and that they form a Pythagorean triple. [In fact, these are the ONLY known set of three triangular numbers that form a Pythagorean triple.]