Question 1159012
f(n+1)=(2(n+1)-1)(2(n+1)+1)-((n+1)-1)
=(2n+2-1)(2n+2+1)-(n)
=(2n+1)(2n+3)-n
Use FOIL
=4n^2+6n+2n+3-n
={{{4n^2+7n+3}}}