a(n) = ((n^2+1)^3) - s, where s is the nearest square to (n^2+1)^3.

Terms

a(0) =-1a(1) =4a(2) =-24a(3) =13a(4) =-113a(5) =28a(6) =-316a(7) =49a(8) =-681a(9) =76a(10) =-1256a(11) =109a(12) =-2089a(13) =148a(14) =-3228a(15) =193a(16) =-4721a(17) =244a(18) =-6616a(19) =301a(20) =-8961a(21) =364a(22) =-11804a(23) =433a(24) =-15193a(25) =508a(26) =-19176a(27) =589a(28) =-23801a(29) =676