deci restul trebuie sa fie un patrat perfect,<100
rest 0 cat0..numarul este 0
rest 1 cat1...nunmaruleste 101
rest4 cat 2...2*100+4=204
rest9 cat3...309
rest16 cat4...416
rest 25 cat5,,,525
rest 36 ...cat 6.....636
rest 49 cat 7...749
rest64 cat 8....864
resi81 , cat 9...981
