Sequence associated with recurrence a(n) = 2*a(n-1) + k*(k+2)*a(n-2).

Terms

a(0) =1a(1) =5a(2) =30a(3) =140a(4) =560a(5) =2016a(6) =6720a(7) =21120a(8) =63360a(9) =183040a(10) =512512a(11) =1397760a(12) =3727360a(13) =9748480a(14) =25067520a(15) =63504384a(16) =158760960a(17) =392232960a(18) =958791680a(19) =2321285120a(20) =5571084288a(21) =13264486400a(22) =31352422400a(23) =73610035200a(24) =171756748800a(25) =398475657216a(26) =919559208960