Given the arithmetic sequence 3.7.11.15.195, how many items are there in this sequence

Given the arithmetic sequence 3.7.11.15.195, how many items are there in this sequence

∵ arithmetic sequence 3.7.11.15.195,
And 7-3 = 4,
So the tolerance is 4,
Let n be 195,
∵an=a1+(n-1)d
∴195=3+4(n-1)
The solution is n = 49
So there are 49 items in this sequence