A153835 The first representative in A014486 for each equivalence class of non-oriented binary tree corresponding to the oriented (plane) binary tree encoded by A014486(n).

0, 1, 2, 2, 4, 4, 6, 4, 4, 9, 9, 11, 9, 9, 14, 14, 14, 9, 9, 14, 11, 9, 9, 23, 23, 25, 23, 23, 28, 28, 28, 23, 23, 28, 25, 23, 23, 37, 37, 39, 37, 37, 42, 42, 37, 23, 23, 37, 25, 23, 23, 42, 42, 39, 28, 28, 37, 28, 23, 23, 37, 28, 25, 23, 23, 65, 65, 67, 65, 65, 70, 70, 70, 65

Offset: 0

Author

Antti Karttunen, Jan 05 2009

Keywords

• nonn

Comments

Any n that occurs in the sequence, occurs for the first time at n (i.e. a(n)=n), thus there are no cases where a(n) > n. A001190(n+1) distinct values occur in each range [A014137(n-1)..A014138(n-1)]. This sequence is similar to A127302 in that it maps all the plane binary trees which belong to the same equivalence class of non-oriented binary trees to one and same integer and likewise, every Catalan bijection whose signature permutation SP satisfies the condition mentioned in A127302, satisfies in a similar way A153835(SP(n)) = A153835(n).

Links

• A. Karttunen, Table of n, a(n) for n = 0..2055

Crossrefs

A127302(a(n)) = A127302(n) holds for all n. Cf. A154103, A069770.