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

Author

Alois P. Heinz, Feb 13 2019

Keywords

• nonn

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.