A324069 Number of defective (binary) heaps on n elements where eight ancestor-successor pairs do not have the correct order.

0, 0, 0, 0, 0, 0, 20, 480, 4830, 40320, 346080, 3014400, 28036800, 271180800, 2723635200, 28751923200, 273405132000, 2754444492800, 29222409216000, 335670386688000, 3786723502848000, 45941770321920000, 580488335032320000, 8000481890598912000

Offset

0,7

Comments

Or number of permutations p of [n] having exactly eight 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=8 of A306393.

Cf. A056971.

Sequence in context: A288034 A272553 A268884 * A065412 A159753 A252975

Adjacent sequences: A324066 A324067 A324068 * A324070 A324071 A324072

Keyword

nonn

Author

Alois P. Heinz, Feb 13 2019

Status

approved