A324067 Number of defective (binary) heaps on n elements where six ancestor-successor pairs do not have the correct order.

0, 0, 0, 0, 0, 8, 100, 720, 5040, 36736, 268800, 2073600, 17186400, 147502080, 1331616000, 13047091200, 110053944000, 1011903692800, 9874978713600, 106953080832000, 1086116967936000, 12275238666240000, 144074916311040000, 1890064025321472000

Offset: 0

Author

Alois P. Heinz, Feb 13 2019

Keywords

• nonn

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.