Number of spanning trees in C_2 X C_n.

Terms

a(0) =2a(1) =32a(2) =294a(3) =2304a(4) =16810a(5) =117600a(6) =799694a(7) =5326848a(8) =34928082a(9) =226195360a(10) =1450199542a(11) =9220780800a(12) =58221203066a(13) =365440965344