a(n) = floor( Bernoulli(2*n)/(-4*n) ).

Terms

a(0) =-1a(1) =0a(2) =-1a(3) =0a(4) =-1a(5) =0a(6) =-1a(7) =0a(8) =-2a(9) =13a(10) =-141a(11) =1803a(12) =-27414a(13) =487468a(14) =-10026348a(15) =236192433a(16) =-6317862398a(17) =190439655626