# Math Help - Sequence Corundum

1. ## Sequence Corundum

kindly help in solving the attached problem
I am stuck in between

2. Originally Posted by mayank
kindly help in solving the attached problem
I am stuck in between
The recurrence relation is solvable to $a_n=\tfrac{c}{2}n(n-1)+2(1-n)(n-1)$ for some constant $c$. Do you see how?

3. Originally Posted by Drexel28
The recurrence relation is solvable to $a_n=\tfrac{c}{2}n(n-1)+2(1-n)(n-1)$ for some constant $c$. Do you see how?
Hey
I have not done this method
but I solved the question by progressions and some logic later on to arrive at answer. My answer is coming out 249. and I know my method is not appropriate can you deduce the answer by recurrence relation