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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
OFFSET
1,2
CROSSREFS
Simple 2-way heap A056971
Sequence in context: A047052 A049662 A264176 * A195854 A153227 A116159
KEYWORD
nonn
AUTHOR
R. H. Hardin May 17 2010
STATUS
approved