A transform of the central binomial coefficients.

Terms

a(0) =1a(1) =1a(2) =4a(3) =7a(4) =21a(5) =46a(6) =127a(7) =309a(8) =832a(9) =2131a(10) =5709a(11) =15010a(12) =40281a(13) =107423a(14) =289314a(15) =778087a(16) =2103361a(17) =5687938a(18) =15427099a(19) =41880357a(20) =113912236a(21) =310148223a(22) =845598389a(23) =2307657222a(24) =6304306171a(25) =17237338021a(26) =47170965082a(27) =129181447969a(28) =354027263457a(29) =970851960736