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A177562
Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, up, up
0
1, 6, 84, 2123, 84034, 4804627, 375435365, 38463186965, 5004563283887, 806386210926308
(list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..10.
CROSSREFS
Sequence in context: A123312 A010794 A177560 * A273935 A318399 A171200
Adjacent sequences: A177559 A177560 A177561 * A177563 A177564 A177565
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved

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Last modified November 29 00:00 EST 2024. Contains 378208 sequences.
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