a(n) = 1 - n^3.

Terms

a(0) =1a(1) =0a(2) =-7a(3) =-26a(4) =-63a(5) =-124a(6) =-215a(7) =-342a(8) =-511a(9) =-728a(10) =-999a(11) =-1330a(12) =-1727a(13) =-2196a(14) =-2743a(15) =-3374a(16) =-4095a(17) =-4912a(18) =-5831a(19) =-6858a(20) =-7999a(21) =-9260a(22) =-10647a(23) =-12166a(24) =-13823a(25) =-15624a(26) =-17575a(27) =-19682a(28) =-21951a(29) =-24388