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A177557 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, up. 0
1, 5, 55, 1062, 31147, 1313796, 75373533, 5661748406, 539467979009, 63618193828712, 9098617148960622, 1551945898935373561, 311275951583298747596, 72535753321856685723563 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

CROSSREFS

Sequence in context: A130031 A336289 A119399 * A158690 A280573 A192723

Adjacent sequences:  A177554 A177555 A177556 * A177558 A177559 A177560

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 10 2010

EXTENSIONS

a(11)-a(14) from Alois P. Heinz, Nov 02 2013

STATUS

approved

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Last modified September 27 10:28 EDT 2021. Contains 347689 sequences. (Running on oeis4.)