Number of unordered pairs of rooted trees with a total of n nodes and an odd total of leaves.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =3a(5) =8a(6) =19a(7) =47a(8) =119a(9) =309a(10) =805a(11) =2115a(12) =5594a(13) =14920a(14) =40037a(15) =108068a(16) =293124a(17) =798739a(18) =2185380a(19) =6001797a(20) =16538728a(21) =45716315a(22) =126727586a(23) =352214041a(24) =981269274a(25) =2739925455a(26) =7666335708a(27) =21491822234a(28) =60358497108a(29) =169798015580