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A324068 Number of defective (binary) heaps on n elements where seven ancestor-successor pairs do not have the correct order. 2
0, 0, 0, 0, 0, 0, 60, 640, 5040, 39424, 315840, 2572800, 22730400, 207820800, 1979577600, 20119756800, 180756576000, 1740900761600, 17732095180800, 197872975872000, 2123068147200000, 24858537099264000, 303091124244480000, 4076808466857984000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

COMMENTS

Or number of permutations p of [n] having exactly seven 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=7 of A306393.

Cf. A056971.

Sequence in context: A081384 A283786 A099344 * A223242 A244837 A268624

Adjacent sequences:  A324065 A324066 A324067 * A324069 A324070 A324071

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Feb 13 2019

STATUS

approved

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Last modified January 29 01:54 EST 2020. Contains 331328 sequences. (Running on oeis4.)