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%I #8 Jul 11 2019 03:51:10
%S 1,1,2,5,7,11,17,27,34,50,65,94,110,154,182,250,279,375,420,555,601,
%T 781,847,1085,1152,1456,1547,1932,2024,2500,2620,3204,3325,4029,4182,
%U 5025,5179,6175,6365,7535,7726,9086,9317,10890,11122,12926,13202,15262,15539
%N Number of (binary) max-heaps on n elements from the set {0,1} containing exactly four 0's.
%H Alois P. Heinz, <a href="/A326505/b326505.txt">Table of n, a(n) for n = 4..10000</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 <a href="/index/Rec#order_13">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-2,1,-1,-4,4,1,-1,2,-2,-1,1).
%F G.f.: -x^4*(2*x^3-x^2+1)*(2*x^6-x^5-x^4+x^3+1)/((x^2+1)^2*(x+1)^4*(x-1)^5).
%Y Column k=4 of A309049.
%K nonn,easy
%O 4,3
%A _Alois P. Heinz_, Jul 09 2019