Number of homeomorphically irreducible (or series-reduced) trees with n pendant nodes, or continua with n non-cut points, or leaves.

A007827

Number of homeomorphically irreducible (or series-reduced) trees with n pendant nodes, or continua with n non-cut points, or leaves.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =7a(7) =13a(8) =32a(9) =73a(10) =190a(11) =488a(12) =1350a(13) =3741a(14) =10765a(15) =31311a(16) =92949a(17) =278840a(18) =847511a(19) =2599071a(20) =8044399a(21) =25082609a(22) =78758786a(23) =248803504a(24) =790411028a(25) =2523668997a(26) =8095146289a(27) =26076714609a(28) =84329102797a(29) =273694746208

External references