the series is 7^2+ 1 , 11^2 +1 , 13^2+1, 17^2+1,....and so on
so we can see that
now we will see the difference of the main number which are
7,11,13,17,19
now
11-7=4
13-11=2
17-13=4
19-17=2
and so on
so we cam to the result that the next number will be 23 in this sub series
so the next number of the series
50,122,170,290,362
will be
23^2+1=529+1=530
50,122,170,290,362 .530
hope you will understand
please reply if any problem.........best of luck