A323964 - OEIS

%I #9 Jun 01 2025 19:56:41

%S 0,896,32460,1201920,29987760,705522048,14197154400,264121228800,

%T 4765553385120,80958196300800,1386261729792960,22797317814635520,

%U 378396940680172800,6210934579834490880,101592763596409536000,1694705349980956262400,27653450672540750745600

%N Number of defective (binary) heaps on n elements with exactly eight defects.

%C Or number of permutations p of [n] having exactly eight indices i in {1,...,n} such that p(i) > p(floor(i/2)).

%H Alois P. Heinz, <a href="/A323964/b323964.txt">Table of n, a(n) for n = 8..200</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Heap.html">Heap</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Binary_heap">Binary heap</a>

%Y Column k=8 of A306343.

%Y Cf. A056971.

%K nonn

%O 8,2

%A _Alois P. Heinz_, Feb 09 2019