A080971 - OEIS

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A080971

A014486-encodings of the trees whose interior zigzag-tree (Stanley's c) is not branch-reduced (in the sense defined by Donaghey).

42, 56, 170, 172, 184, 202, 212, 226, 232, 240, 682, 684, 690, 692, 696, 714, 724, 738, 744, 752, 810, 812, 824, 842, 850, 852, 856, 880, 906, 908, 916, 930, 936, 944, 962, 964, 968, 976, 992, 2730, 2732, 2738, 2740, 2744, 2762, 2764, 2770, 2772, 2776, 2786

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

Table of n, a(n) for n=0..49.

Robert Donaghey, Automorphisms on Catalan trees and bracketing, J. Combin. Theory, Series B, 29 (1980), 75-90.

Antti Karttunen, Initial terms illustrated in positions 4, 8, 9, 10, 13, 14, 17, 19, 21, 22, 23, 24, 25, 26, 27, 28, 31, ...

FORMULA

a(n) = A014486(A080970(n)).

CROSSREFS

Cf. A014486, A080970, A080981.

Sequence in context: A043916 A124656 A002706 * A039384 A043207 A043987

Adjacent sequences: A080968 A080969 A080970 * A080972 A080973 A080974

KEYWORD

nonn

AUTHOR

Antti Karttunen, Mar 02 2003

STATUS

approved