a(n) = Sum_{t=0..n} g(t)*g(n-t) where g(t) = A002121(t).

Terms

a(0) =1a(1) =0a(2) =-2a(3) =2a(4) =3a(5) =-4a(6) =-1a(7) =8a(8) =-1a(9) =-10a(10) =9a(11) =16a(12) =-18a(13) =-12a(14) =42a(15) =4a(16) =-58a(17) =40a(18) =82a(19) =-88a(20) =-54a(21) =188a(22) =18a(23) =-248a(24) =151a(25) =354a(26) =-338a(27) =-260a(28) =760a(29) =120