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A324069
Number of defective (binary) heaps on n elements where eight ancestor-successor pairs do not have the correct order.
2
0, 0, 0, 0, 0, 0, 20, 480, 4830, 40320, 346080, 3014400, 28036800, 271180800, 2723635200, 28751923200, 273405132000, 2754444492800, 29222409216000, 335670386688000, 3786723502848000, 45941770321920000, 580488335032320000, 8000481890598912000
OFFSET
0,7
COMMENTS
Or number of permutations p of [n] having exactly eight pairs (i,j) in {1,...,n} X {1,...,floor(log_2(i))} such that p(i) > p(floor(i/2^j)).
LINKS
Eric Weisstein's World of Mathematics, Heap
Wikipedia, Binary heap
Wikipedia, Permutation
CROSSREFS
Column k=8 of A306393.
Cf. A056971.
Sequence in context: A288034 A272553 A268884 * A065412 A159753 A252975
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 13 2019
STATUS
approved