Erroneous version of A080937.

Terms

a(0) =1a(1) =2a(2) =5a(3) =14a(4) =42a(5) =131a(6) =417a(7) =1341a(8) =4334a(9) =14042a(10) =45562a(11) =148029a(12) =481804a(13) =1572625a(14) =5156025a(15) =17018505a(16) =56717910a(17) =191540940a(18) =658084182a(19) =2309516616