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A324067 Number of defective (binary) heaps on n elements where six ancestor-successor pairs do not have the correct order. 2
0, 0, 0, 0, 0, 8, 100, 720, 5040, 36736, 268800, 2073600, 17186400, 147502080, 1331616000, 13047091200, 110053944000, 1011903692800, 9874978713600, 106953080832000, 1086116967936000, 12275238666240000, 144074916311040000, 1890064025321472000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

Or number of permutations p of [n] having exactly six pairs (i,j) in {1,...,n} X {1,...,floor(log_2(i))} such that p(i) > p(floor(i/2^j)).

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..200

Eric Weisstein's World of Mathematics, Heap

Wikipedia, Binary heap

Wikipedia, Permutation

CROSSREFS

Column k=6 of A306393.

Cf. A056971.

Sequence in context: A286841 A316870 A181034 * A083227 A261742 A222486

Adjacent sequences:  A324064 A324065 A324066 * A324068 A324069 A324070

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Feb 13 2019

STATUS

approved

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Last modified May 22 09:50 EDT 2022. Contains 353949 sequences. (Running on oeis4.)