n(n+180) is a square.

Terms

a(0) =-2116a(1) =-768a(2) =-500a(3) =-324a(4) =-240a(5) =-196a(6) =-192a(7) =-180a(8) =0a(9) =12a(10) =16a(11) =60a(12) =144a(13) =320a(14) =588a(15) =1936