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A178010
Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/5)] (5-way heap).
3
1, 1, 1, 2, 6, 24, 120, 360, 1680, 10080, 72576, 604800, 3326400, 26611200, 259459200, 2905943040, 36324288000, 290594304000, 3293402112000, 44460928512000, 675806113382400, 11263435223040000, 118266069841920000, 1734569024348160000, 29921315670005760000
OFFSET
0,4
LINKS
Wikipedia, D-ary heap
CROSSREFS
Simple 2-way heap A056971.
Column k=5 of A273693.
Sequence in context: A189564 A276839 A364425 * A366368 A355988 A330043
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 17 2010
EXTENSIONS
a(0), a(21)-a(24) from Alois P. Heinz, May 27 2016
STATUS
approved