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%I #30 Oct 06 2022 12:32:53
%S 1,1,2,5,14,42,133,442,1535,5546,20754,80113,317875,1292648,5374073,
%T 22794182,98462847,432498659,1929221610,8728815103,40017844229,
%U 185727603829,871897549029,4137132922197,19828476952117,95934298966615,468291607852143,2305162065138433
%N Number of ascent sequences avoiding the pattern 120.
%C It appears that no formula or g.f. is known.
%H Liang Chengwei, Shi Lecun and Cai Zhongyu, <a href="/A202061/b202061.txt">Table of n, a(n) for n = 0..500</a> (terms 0..74 from Andrew Conway and Miles Conway)
%H Andrew R. Conway, Miles Conway, Andrew Elvey Price and Anthony J. Guttmann, <a href="https://arxiv.org/abs/2111.01279">Pattern-avoiding ascent sequences of length 3</a>, arXiv:2111.01279 [math.CO], Nov 01 2021.
%H Paul Duncan and Einar Steingrimsson, <a href="http://arxiv.org/abs/1109.3641">Pattern avoidance in ascent sequences</a>, arXiv preprint arXiv:1109.3641 [math.CO], 2011.
%Y Total number of ascent sequences is given by A022493. Number of ascent sequences avoiding 001 (and others) is A000079; 102 is A007051; 101 is A000108; 000 is A202058; 100 is A202059; 110 is A202060; 120 is A202061; 201 is A202062; 210 is A108304; 0123 is A080937; 0021 is A007317.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Dec 10 2011
%E More terms from _Anthony Guttmann_, Nov 04 2021
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