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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..9.

CROSSREFS

Simple 2-way heap A056971

Sequence in context: A108792 A265854 A128013 * A134262 A240289 A001536

Adjacent sequences:  A178018 A178019 A178020 * A178022 A178023 A178024

KEYWORD

nonn

AUTHOR

R. H. Hardin May 17 2010

STATUS

approved

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Last modified May 19 13:27 EDT 2019. Contains 323393 sequences. (Running on oeis4.)