a(n) is the number of unlabeled unrooted trees (as in A000055) on n nodes with one designated node (exclusive) or one designated edge.

A328779

a(n) is the number of unlabeled unrooted trees (as in A000055) on n nodes with one designated node (exclusive) or one designated edge.

Terms

    a(0) =0a(1) =1a(2) =2a(3) =3a(4) =7a(5) =15a(6) =36a(7) =85a(8) =211a(9) =525a(10) =1341a(11) =3449a(12) =9001a(13) =23671a(14) =62835a(15) =167881a(16) =451557a(17) =1221065a(18) =3318737a(19) =9059397a(20) =24830110a(21) =68299159a(22) =188488448a(23) =521737636a(24) =1448154837a(25) =4029712400a(26) =11239492056a(27) =31416403198a(28) =87990722479a(29) =246903542031

External references