login
A177618
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, up, down
0
1, 20, 1680, 364758, 162161006, 128434364522, 165062027642714, 321840048409989468
OFFSET
1,2
CROSSREFS
Sequence in context: A177600 A177607 A177612 * A177624 A177613 A177619
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved