There are lots of answers for m and a (when they’re positive whole numbers).
For example, m=2, a=58, because
m=5, a=156, because
m=8, a=254, because
The next value of m is 3 more than the last (8+3=11). To find a, use the formula:
(98m-22)/3. When m=11, a=352. a increases by 98 each time.
I hope this is what your question is looking for. I don’t know why you should subtract 5, but if you do you will start with m=1 and a=27, followed by m=4 (an increase of 3) and a=125 (an increase of 98).