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A058889 Arrange binary trees in natural sequential order (see examples); sequence gives numbers of nodes. 0
1, 2, 3, 3, 4, 4, 4, 5, 5, 6, 4, 4, 5, 5, 6, 6, 6, 5, 5, 6, 6, 7, 7, 7, 7, 8, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 7, 7, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..99.

EXAMPLE

The trees are x, (x,x), (x,(x,x)), ((x,x),x), ((x,x),(x,x)), (x,(x,(x,x))), ((x,(x,x)),x), ((x,x),(x,(x,x))), ((x,(x,x)),(x,x)), ((x,(x,x)),(x,(x,x))) (x,((x,x),x)), (((x,x),x),x), ((x,x)((x,x),x)), (((x,x),x),(x,x)), ((x,(xx)), ((x,x),x)),...

CROSSREFS

Cf. A000108.

Sequence in context: A156077 A189641 A189672 * A226143 A166724 A110862

Adjacent sequences:  A058886 A058887 A058888 * A058890 A058891 A058892

KEYWORD

nonn,nice,easy

AUTHOR

Claude Lenormand (claude.lenormand(AT)free.fr), Jan 08 2001

EXTENSIONS

More terms from John W. Layman, Feb 03 2003

STATUS

approved

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Last modified March 26 04:32 EDT 2019. Contains 321481 sequences. (Running on oeis4.)