Let the first digit be a, second be b, third be c
a = 3c
This would mean that a is either 0,3,6, or 9, a cannot be 0 since we have a 3-digit number.
(a , c) = {(3,1), (6,2), (9,3)}
a - 1 = b + c
3c - 1 = b + c
2c - 1 = b
(b , c) = {(1.1), (3,2), (5,3)}
The possible numbers are 311, 632, and 953.
