# Is it dissolvable! sorry divisible -part 2!

The integers $$a,b$$ are selected from $$5n$$ consecutive integers: $${1,2,3,4, \ldots, 5n-1,5n}$$. Find the sum of the digits of number of unordered ways can these integers be selected , such that $$a^2-b^2$$ is divisible by 5 when $$n=100$$.

×