A sequence is generated by the recurrence relation Ur+1 = 1/Ur -3. Given that U2 = U1 find the possible of U1

Answer 1

U1=U1
U2=U1
U3=U3
U4=U4
for r>3, we have
U5 = 1/U1 = 1/U1
U6 = 1/U2 = 1/U1
U7 = 1/U3
Without some info about U3 and U4, I don't see what we can deduce.