a(n) = number of "lonesum" 2 X 2 X n tensors.

Terms

a(0) =1a(1) =14a(2) =104a(3) =644a(4) =3668a(5) =19964a(6) =105764a(7) =550844a(8) =2836868a(9) =14498204a(10) =73695524a(11) =373141244a(12) =1883894468a(13) =9490820444a(14) =47735267684a(15) =239788294844