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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
OFFSET
4,3
LINKS
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
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Jul 09 2019
STATUS
approved