sorry i should have been a bit clearer.
I am wanting to know why:
2^2+3^2+6^2=7^2
(the ^2 represents squared).
I know that the product of any two consecutive numbers squared plus 1 is the answer.
To put this in to practice:
3^2+4^2+12^2=13^2
(my consecutive numbers are 3 and 4 with a product of 12- add one to equal 13 and all of these numbers are squared.)