Let ???????? be the ????-th Fibonacci number. In this paper, we show that the only nonnegative solutions (????, ????, ????) of the Diophantine equation ???? 2 ???? + ???? 2 ???? = 2 ???? with ???? ≥ ???? ≥ 0 are (1, 0, 0), (2, 0, 0), (3, 0, 2), (6, 0, 6), (1, 1, 1), (2, 1, 1), (2, 2, 1), (3, 3, 3), (6, 6, 7)
Jeong et al. (Mon,) studied this question.