Let the nth number be
100x + 8
the (n+1)st number be 1000x + 308
the difference is 900x + 300 = 300(3x + 1)
if 100x + 8 = 0 mod 19
then 5x + 8 = 0 mod 19
20x + 32 = 0 mod 19
or x + 13 = 0 mod 19
or 3x + 39 = 0 mod 19
or 3x +1 = 0 mod 19
so difference is divisible by 19 if nth number is divisible by 19
1st number is divisible by 19 and hence the difference and and so the second one
using the logic above we see that next one and so so
I have proved by mathematical induction
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