Problem 72 - more J

I haven't gotten around to solving too many problems recently because of finals, but I decided to take a couple of minutes and look at the problems that were coming up. As I still had J free, I managed to find a problem which took me under a minute to solve in J. Below is my solution to problem 72 in J, solution runs in about 8 seconds.

+/5 p:}.}.i.1000001