Number of series-reduced trees with n nodes.

Terms

a(0) =0a(1) =1a(2) =1a(3) =0a(4) =1a(5) =1a(6) =2a(7) =2a(8) =4a(9) =5a(10) =10a(11) =14a(12) =26a(13) =42a(14) =78a(15) =132a(16) =249a(17) =445a(18) =842a(19) =1561a(20) =2988a(21) =5671a(22) =10981a(23) =21209a(24) =41472a(25) =81181a(26) =160176a(27) =316749a(28) =629933a(29) =1256070