A324068 Number of defective (binary) heaps on n elements where seven ancestor-successor pairs do not have the correct order.

0, 0, 0, 0, 0, 0, 60, 640, 5040, 39424, 315840, 2572800, 22730400, 207820800, 1979577600, 20119756800, 180756576000, 1740900761600, 17732095180800, 197872975872000, 2123068147200000, 24858537099264000, 303091124244480000, 4076808466857984000

Offset

0,7

Comments

Or number of permutations p of [n] having exactly seven 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=7 of A306393.

Cf. A056971.

Sequence in context: A081384 A283786 A099344 * A223242 A244837 A268624

Adjacent sequences: A324065 A324066 A324067 * A324069 A324070 A324071

Keyword

nonn

Author

Alois P. Heinz, Feb 13 2019

Status

approved