Binomial transform of A001651.

Terms

a(0) =1a(1) =3a(2) =9a(3) =24a(4) =60a(5) =144a(6) =336a(7) =768a(8) =1728a(9) =3840a(10) =8448a(11) =18432a(12) =39936a(13) =86016a(14) =184320a(15) =393216a(16) =835584a(17) =1769472a(18) =3735552a(19) =7864320a(20) =16515072a(21) =34603008a(22) =72351744a(23) =150994944a(24) =314572800a(25) =654311424a(26) =1358954496a(27) =2818572288a(28) =5838471168a(29) =12079595520