A326505 Number of (binary) max-heaps on n elements from the set {0,1} containing exactly four 0's.

1, 1, 2, 5, 7, 11, 17, 27, 34, 50, 65, 94, 110, 154, 182, 250, 279, 375, 420, 555, 601, 781, 847, 1085, 1152, 1456, 1547, 1932, 2024, 2500, 2620, 3204, 3325, 4029, 4182, 5025, 5179, 6175, 6365, 7535, 7726, 9086, 9317, 10890, 11122, 12926, 13202, 15262, 15539

Offset

4,3

Links

Alois P. Heinz, Table of n, a(n) for n = 4..10000

Eric Weisstein's World of Mathematics, Heap

Wikipedia, Binary heap

Index entries for linear recurrences with constant coefficients, signature (1,2,-2,1,-1,-4,4,1,-1,2,-2,-1,1).

Formula

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).

Crossrefs

Column k=4 of A309049.

Sequence in context: A077128 A106008 A138244 * A019396 A153767 A038973

Adjacent sequences: A326502 A326503 A326504 * A326506 A326507 A326508

Keyword

nonn,easy

Author

Alois P. Heinz, Jul 09 2019

Status

approved