1) 16, 36 si 64
2) a= 5⁴+5⁵+5⁶+5⁷= 5⁴(1+5+25+125)= 156*5⁴= 2*2*3*13*5⁴
deci cel mai mare divizor prim este 13
3) a=4⁹+4¹²= 4⁹(1+64)=65*4⁹= 5*13*4⁹
Divizorii impari sunt 5 si 13
D450= {2,3,5,6,9,10,15,18,25,30,45,50,75,90,150,225, 450}
2+3+5+6+10+15+18+30+45+50+75+90+150+450=
(faci tu calculul)