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%I #9 Nov 05 2025 15:22:23
%S 0,0,0,4,30,168,840,3960,18018,80080,350064,1511640,6466460,27457584,
%T 115892400,486748080,2035917450,8485840800,35263382880,146157442200,
%U 604404010980,2494365759600,10275832148400,42264944401680,173588164506900,712027089322848,2917167840871200,11938779496898800
%N 2*A002740(n).
%H Luca Ferrari and Emanuele Munarini, <a href="https://arxiv.org/abs/1203.6807">Enumeration of saturated chains in Dyck lattices</a>, arXiv preprint arXiv:1203.6807, 2012
%Y Cf. A002740.
%K nonn
%O 0,4
%A _N. J. A. Sloane_, Oct 03 2012