Number of general plane trees which are either empty (the case a(0)), or whose root degree is either 1 (i.e., the planted trees) or the two leftmost subtrees (of the root node) are identical.
A073190
Number of general plane trees which are either empty (the case a(0)), or whose root degree is either 1 (i.e., the planted trees) or the two leftmost subtrees (of the root node) are identical.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =3a(4) =8a(5) =20a(6) =60a(7) =181a(8) =584a(9) =1916a(10) =6476a(11) =22210a(12) =77416a(13) =272840a(14) =971640a(15) =3488925a(16) =12621168a(17) =45946156a(18) =168206604a(19) =618853270a(20) =2286974856a(21) =8485246456a(22) =31596023208a(23) =118037654258a(24) =442287721872
External references
- oeis: A073190