Numbers of not uniquely embeddable trees on n vertices.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =4a(8) =16a(9) =49a(10) =140a(11) =390a(12) =1039a(13) =2724a(14) =7058a(15) =18239a(16) =46964a(17) =121322a(18) =314155a(19) =817407a(20) =2136273a(21) =5611821a(22) =14811062a(23) =39275823a(24) =104603284a(25) =279746752a(26) =751001466a(27) =2023355751a(28) =5469448788a(29) =14830713681