login
A178021
Number of permutations of 3 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap)
0
1, 10, 250, 22500, 2788800, 1002405600, 359463283200, 326108342112000, 257963213378304000
OFFSET
1,2
CROSSREFS
Simple 2-way heap A056971
Sequence in context: A108792 A265854 A128013 * A134262 A240289 A001536
KEYWORD
nonn
AUTHOR
R. H. Hardin May 17 2010
STATUS
approved