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A326505 Number of (binary) max-heaps on n elements from the set {0,1} containing exactly four 0's. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 31 13:01 EDT 2020. Contains 334748 sequences. (Running on oeis4.)