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A178019
Number of permutations of 3 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/4)] (4-way heap)
0
1, 7, 170, 8870, 976720, 216658080, 99152064000, 32300260082400
OFFSET
1,2
CROSSREFS
Simple 2-way heap A056971
Sequence in context: A172027 A113562 A157203 * A337676 A266306 A332117
KEYWORD
nonn
AUTHOR
R. H. Hardin May 17 2010
STATUS
approved