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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). 5
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

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

PROG

(MIT Scheme:) (define (*A153835! s) (cond ((pair? s) (*A153835! (car s)) (*A153835! (cdr s)) (if (= 1 (A154103bi (parenthesization->A014486 (car s)) (parenthesization->A014486 (cdr s)))) (*A069770! s)))) s)

CROSSREFS

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

Sequence in context: A324104 A278233 A128923 * A338098 A171462 A075857

Adjacent sequences:  A153832 A153833 A153834 * A153836 A153837 A153838

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 05 2009

STATUS

approved

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Last modified May 13 18:37 EDT 2021. Contains 343868 sequences. (Running on oeis4.)