Originally Posted by
TheEmptySet Notice for $\displaystyle n \ge 5 $ each term is divisable by 10 so they have a remainder of zero(why)
Now we only need to worry about the first 4 terms
We also don't need to worry about the 4 term (why)
so we get $\displaystyle (2)1+(6)2+12(6)=86$ so the remainder is 6