a(n) = nearest integer to k^2*sin(sqrt(k)+j*Pi/2) where n = 3*k+j, 0<=j<3.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =-1a(6) =4a(7) =1a(8) =-4a(9) =9a(10) =-1a(11) =-9a(12) =15a(13) =-7a(14) =-15a(15) =20a(16) =-15a(17) =-20a(18) =23a(19) =-28a(20) =-23a(21) =23a(22) =-43a(23) =-23a(24) =20a(25) =-61a(26) =-20a(27) =11a(28) =-80a(29) =-11