A324066 Number of defective (binary) heaps on n elements where five ancestor-successor pairs do not have the correct order.

0, 0, 0, 0, 0, 16, 120, 720, 4830, 31360, 211680, 1555200, 11880000, 95293440, 815443200, 7687680000, 60432372000, 530552422400, 4945330790400, 51912327168000, 496766020608000, 5425624055808000, 61093281300480000, 781258429366272000, 8157685988035584000

Offset

0,6

Comments

Or number of permutations p of [n] having exactly five 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=5 of A306393.

Cf. A056971.

Sequence in context: A010932 A014805 A022611 * A164542 A351383 A027049

Adjacent sequences: A324063 A324064 A324065 * A324067 A324068 A324069

Keyword

nonn

Author

Alois P. Heinz, Feb 13 2019

Status

approved