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A279201
Number of Wilf-equivalence classes of square permutations of 2n things that avoid 123.
1
1, 2, 12, 118, 1218, 14272
OFFSET
0,2
LINKS
Samuele Giraudo, S. Vialette, Unshuffling Permutations, arXiv preprint arXiv:1601.05962 [cs.DS], 2016.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Dec 15 2016
STATUS
approved