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A177563 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, down. 0
1, 6, 88, 2328, 96886, 5841912, 482051408, 52197308928, 7182160372912, 1224288015648528, 253281233443497344, 62522722555285781376, 18154991497984902599824, 6126411246446756437747008 (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: A265267 A218260 A177567 * A177569 A327645 A309165

Adjacent sequences:  A177560 A177561 A177562 * A177564 A177565 A177566

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 March 28 20:01 EDT 2020. Contains 333103 sequences. (Running on oeis4.)