A178014 Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/4)] (4-way heap)

1, 3, 18, 189, 3000, 84060, 2799360, 148771080, 8457799680, 727583990400, 53828906153760

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Crossrefs

Simple 2-way heap A056971

Sequence in context: A279843 A355101 A355107 * A258659 A363414 A002824

Adjacent sequences: A178011 A178012 A178013 * A178015 A178016 A178017

Keyword

nonn

Author

R. H. Hardin May 17 2010

Status

approved