a(n) = n^2 - (n-1)^2 - (n-2)^2 - ... - 1^2.

Terms

a(0) =1a(1) =3a(2) =4a(3) =2a(4) =-5a(5) =-19a(6) =-42a(7) =-76a(8) =-123a(9) =-185a(10) =-264a(11) =-362a(12) =-481a(13) =-623a(14) =-790a(15) =-984a(16) =-1207a(17) =-1461a(18) =-1748a(19) =-2070a(20) =-2429a(21) =-2827a(22) =-3266a(23) =-3748a(24) =-4275a(25) =-4849a(26) =-5472a(27) =-6146a(28) =-6873a(29) =-7655