Number of Hamiltonian paths in P_4 X P_n.

Terms

a(0) =1a(1) =14a(2) =62a(3) =276a(4) =1006a(5) =3610a(6) =12010a(7) =38984a(8) =122188a(9) =375122a(10) =1128446a(11) =3342794a(12) =9767588a(13) =28217820a(14) =80709424a(15) =228864620a(16) =644060262a(17) =1800346140a(18) =5002457832a(19) =13825549136a(20) =38026348240a(21) =104133664506a(22) =284037629690a(23) =771953153918