Exponential (or binomial) half-convolution of A000032 (Lucas) with itself.

Terms

a(0) =4a(1) =2a(2) =8a(3) =17a(4) =84a(5) =177a(6) =737a(7) =1857a(8) =7732a(9) =19457a(10) =78223a(11) =203777a(12) =809145a(13) =2134017a(14) =8349013a(15) =22347777a(16) =86533892a(17) =234029057a(18) =897748577a(19) =2450784257a(20) =9328491339a(21) =25664946177a(22) =97021416973a(23) =268766806017