a=2015x² + 2016ⁿ + 2017
Uc(a)=Uc(2015x² +2016ⁿ + 2017)
Uc(2015x²)=5 sau 0 deoarece un patrat perfect inmultit cu 5 se termina in 5 sau 0
Uc(2016ⁿ)=6 sau 1 6 la orice putere =6 daca n=0 2016⁰=1
caz 1 x² =numar impar n>0
Uc(a)=Uc(2015x² +2016ⁿ + 2017)=Uc(5+6+7)=Uc(18)=8
caz 2 x² =numar par n>0
Uc(a)=Uc(2015x² +2016ⁿ + 2017)=Uc(0+6+7)=Uc(13)=3
caz 3 x² =numar impar n=0
Uc(a)=Uc(2015x² +2016ⁿ + 2017)=Uc(5+1+7)=Uc(13)=3
caz 3 x² =numar par n=0
Uc(a)=Uc(2015x² +2016ⁿ + 2017)=Uc(0+1+7)=Uc(8)=8
daca ultima cifra a unui numar est 2,3 7 sau 8 acest numar nu este patrat perfect