|
%I #6 Feb 24 2019 15:39:17
%S 0,0,0,0,0,0,60,640,5040,39424,315840,2572800,22730400,207820800,
%T 1979577600,20119756800,180756576000,1740900761600,17732095180800,
%U 197872975872000,2123068147200000,24858537099264000,303091124244480000,4076808466857984000
%N Number of defective (binary) heaps on n elements where seven ancestor-successor pairs do not have the correct order.
%C 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)).
%H Alois P. Heinz, <a href="/A324068/b324068.txt">Table of n, a(n) for n = 0..200</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Heap.html">Heap</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Binary_heap">Binary heap</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation">Permutation</a>
%Y Column k=7 of A306393.
%Y Cf. A056971.
%K nonn
%O 0,7
%A _Alois P. Heinz_, Feb 13 2019
|
