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A178018
Number of permutations of 3 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/3)] (3-way heap).
0
1, 5, 94, 4480, 332680, 44019800, 10480204080, 3225666791760, 1530272351292180
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OFFSET
1,2
LINKS
Table of n, a(n) for n=1..9.
CROSSREFS
Simple 2-way heap
A056971
Sequence in context:
A047052
A049662
A264176
*
A195854
A153227
A116159
Adjacent sequences:
A178015
A178016
A178017
*
A178019
A178020
A178021
KEYWORD
nonn
AUTHOR
R. H. Hardin
, May 17 2010
STATUS
approved
