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A229393 Number of shapes of balanced 8-ary trees with n nodes, where a tree is balanced if the total number of nodes in subtrees corresponding to the branches of any node differ by at most one. 2
1, 1, 8, 28, 56, 70, 56, 28, 8, 1, 64, 1792, 28672, 286720, 1835008, 7340032, 16777216, 16777216, 469762048, 5754585088, 40282095616, 176234168320, 493455671296, 863547424768, 863547424768, 377801998336, 6044831973376, 42313823813632, 169255295254528 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n) = 1 for n in { A023001 }.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..585

MAPLE

a:= proc(n) option remember; local m, r; if n<2 then 1 else

      r:= iquo(n-1, 8, 'm'); binomial(8, m) *a(r+1)^m *a(r)^(8-m) fi

    end:

seq(a(n), n=0..73);

CROSSREFS

Column k=8 of A221857.

Sequence in context: A009504 A001486 A230211 * A173681 A045850 A264354

Adjacent sequences:  A229390 A229391 A229392 * A229394 A229395 A229396

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Sep 21 2013

STATUS

approved

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Last modified July 4 17:20 EDT 2022. Contains 355083 sequences. (Running on oeis4.)