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%I #19 Mar 12 2021 19:26:03
%S 1,1,6,90,2520,112681,7368841,663399996,78683697960,11891546908080,
%T 2230852444731961,508662924427157281,138544315556694333336,
%U 44427011758118629606980,16567455622575976083141540,7109119064485787682672633841,3478010197625548606811131876321
%N Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, up, up.
%H Mingjia Yang and Doron Zeilberger, <a href="https://arxiv.org/abs/1805.06077">Increasing Consecutive Patterns in Words</a>, arXiv:1805.06077 [math.CO], 2018.
%H Mingjia Yang, <a href="https://doi.org/10.7282/t3-d9z1-aw94">An experimental walk in patterns, partitions, and words</a>, Ph. D. Dissertation, Rutgers University (2020).
%Y Cf. A177558, A177574, A177594.
%K nonn
%O 0,3
%A _R. H. Hardin_, May 10 2010
%E a(12)-a(14) from _Alois P. Heinz_, Nov 01 2013
%E a(0), a(15)-a(16) from _Alois P. Heinz_, Aug 08 2018
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