The simplest answer is
t(n) = 36 + 4n for n = 1, 2, 3, ...
42, 44, 45, 46, 48, 49.
They are: 24 28 32 36 40 44 and 48
Add them up. 40, 42, 44, 45, 46, 48, 49, 50
44, 48.
40, 42, 44, 45, 46, 48, 49, 50
1st = 12 then 16 20 24 28 32 36 40 44 so 10th = 48
4 8 12 16 20 24 28 32 36 40 44 48 52 56 60
40, 42, 44, 45, 46, 48, 49, 50
40, 42, 44, 45, 46, 48, 49, 50.
40, 42, 44, 45, 46, 48, 49, 50
The only number in that list that doesn't divide by 4 is 38.
Add them up. 40, 42, 44, 45, 46, 48, 49, 50