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A324071
Number of defective (binary) heaps on n elements where ten ancestor-successor pairs do not have the correct order.
2
0, 0, 0, 0, 0, 0, 0, 80, 3150, 36736, 359520, 3532800, 36115200, 383708160, 4247443200, 48673996800, 515675160000, 5654852403200, 64785924403200, 788119068672000, 9695238119424000, 125961866477568000, 1700829800017920000, 24580421999198208000
OFFSET
0,8
COMMENTS
Or number of permutations p of [n] having exactly ten 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=10 of A306393.
Cf. A056971.
Sequence in context: A328875 A154307 A233950 * A017796 A035735 A035805
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 13 2019
STATUS
approved