The sequence (an)(a_n)(an) is defined by an≡2an−1+1(mod5)a_n \equiv 2a_{n-1} + 1 \pmod{5}an≡2an−1+1(mod5) with a0≡1(mod5)a_0 \equiv 1 \pmod{5}a0≡1(mod5). What is a4(mod5)a_4 \pmod{5}a4(mod5)?
000
111
222
444