A178010 Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/5)] (5-way heap).

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

Alois P. Heinz, Table of n, a(n) for n = 0..484

Wikipedia, D-ary heap

Crossrefs

Simple 2-way heap A056971.

Column k=5 of A273693.

Sequence in context: A189564 A276839 A364425 * A366368 A355988 A330043

Adjacent sequences: A178007 A178008 A178009 * A178011 A178012 A178013

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