Question 392911
The recursion formula is a(n) = a(n-1) + 2*(n-1) = a(n-2) + 2*(n-2) + 2*(n-1) = a(n-3) + 2*(n-3) + 2*(n-2) + 2*(n-1) = ... = a(1) + 2*1 + 2*2 + ... + 2*(n-2) + 2*(n-1) = 2 + 2(1 + 2 + ..+ (n-2) + (n - 1)) = 2 + (n - 1)n = {{{n^2 - n + 2}}}.

Therefore {{{ a(n) = n^2- n + 2}}}.