a(1) = 1, then add, subtract and multiply 2, 3, 4; 5, 6, 7; ... in that order.

Terms

a(0) =1a(1) =3a(2) =0a(3) =0a(4) =5a(5) =-1a(6) =-7a(7) =1a(8) =-8a(9) =-80a(10) =-69a(11) =-81a(12) =-1053a(13) =-1039a(14) =-1054a(15) =-16864a(16) =-16847a(17) =-16865a(18) =-320435a(19) =-320415a(20) =-320436a(21) =-7049592a(22) =-7049569a(23) =-7049593a(24) =-176239825a(25) =-176239799a(26) =-176239826a(27) =-4934715128a(28) =-4934715099a(29) =-4934715129