1. ## Determine

Let $a, b, c$and $d$ be prime numbers

such that $a > 3b > 6c > 12d$

and

$a^2-b^2 +c^2-d^2 = 1749.$

Determine all possible values of

$a^2 +b^2 +c^2 +d^2$ .

2. I haven't solved it, but it here's what could be an important clue: d = 2