Array read by antidiagonals: T(m,n) = number of Eulerian cycles in the torus grid graph C_m X C_n.

Terms

a(0) =2a(1) =4a(2) =4a(3) =8a(4) =40a(5) =8a(6) =16a(7) =320a(8) =320a(9) =16a(10) =32a(11) =2368a(12) =8616a(13) =2368a(14) =32a(15) =64a(16) =16832a(17) =207496a(18) =207496a(19) =16832a(20) =64a(21) =128a(22) =116608a(23) =4788808a(24) =15639936a(25) =4788808a(26) =116608a(27) =128a(28) =256a(29) =793088