Give a recursive denition with initial condition$($s$)$ for the following sequence $\{a_n\}.$

For $n=1,2,3,$dots

a$)a_n=4n-2.$

b$)a_n=1+(-1{)}^n.$

c$)a_n=n(n+1).$

d$)a_n=n^2.$

e$)a_n={10}^n.$