This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A324070 #7 Feb 16 2025 08:33:57
%S A324070 0,0,0,0,0,0,0,240,4200,39424,359520,3340800,32630400,331499520,
%T A324070 3503385600,38504294400,386486100000,4064835174400,44847772569600,
%U A324070 530121646080000,6258102529536000,78618109870080000,1027628834918400000,14504975258222592000
%N A324070 Number of defective (binary) heaps on n elements where nine ancestor-successor pairs do not have the correct order.
%C A324070 Or number of permutations p of [n] having exactly nine pairs (i,j) in {1,...,n} X {1,...,floor(log_2(i))} such that p(i) > p(floor(i/2^j)).
%H A324070 Alois P. Heinz, <a href="/A324070/b324070.txt">Table of n, a(n) for n = 0..200</a>
%H A324070 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Heap.html">Heap</a>
%H A324070 Wikipedia, <a href="https://en.wikipedia.org/wiki/Binary_heap">Binary heap</a>
%H A324070 Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation">Permutation</a>
%Y A324070 Column k=9 of A306393.
%Y A324070 Cf. A056971.
%K A324070 nonn
%O A324070 0,8
%A A324070 _Alois P. Heinz_, Feb 13 2019