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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 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 April 6 11:51 EDT 2020. Contains 333273 sequences. (Running on oeis4.)