OFFSET
4,2
COMMENTS
Or number of permutations p of [n] having exactly four indices i in {1,...,n} such that p(i) > p(floor(i/2)).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 4..200
Eric Weisstein's World of Mathematics, Heap
Wikipedia, Binary heap
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 09 2019
STATUS
approved