Number of 5-step knight's tours on an (n+2) X (n+2) board summed over all starting positions.

Terms

a(0) =16a(1) =400a(2) =2800a(3) =9328a(4) =21480a(5) =39616a(6) =63440a(7) =92656a(8) =127264a(9) =167264a(10) =212656a(11) =263440a(12) =319616a(13) =381184a(14) =448144a(15) =520496a(16) =598240a(17) =681376a(18) =769904a(19) =863824a(20) =963136a(21) =1067840a(22) =1177936a(23) =1293424a(24) =1414304a(25) =1540576a(26) =1672240a(27) =1809296a(28) =1951744a(29) =2099584