Number of compositions of 2n in which each part has even multiplicity.

Terms

a(0) =1a(1) =1a(2) =2a(3) =8a(4) =24a(5) =72a(6) =264a(7) =952a(8) =3352a(9) =11960a(10) =43656a(11) =160840a(12) =594568a(13) =2215480a(14) =8300056a(15) =31191480a(16) =117674504a(17) =445439944a(18) =1691011464a(19) =6437425720a(20) =24564925848a(21) =93937631544a(22) =359943235080