A324064 Number of defective (binary) heaps on n elements where three ancestor-successor pairs do not have the correct order.

0, 0, 0, 0, 6, 24, 120, 640, 3150, 16128, 94080, 614400, 3801600, 26864640, 203174400, 1757184000, 11783772000, 95122227200, 794598604800, 7821066240000, 65767223808000, 675845406720000, 6895980748800000, 83909612666880000, 784784318782464000

Offset: 0

Author

Alois P. Heinz, Feb 13 2019

Keywords

• nonn

Comments

Or number of permutations p of [n] having exactly three 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=3 of A306393.

Cf. A056971.