

A202061


Number of ascent sequences avoiding the pattern 120.


5



1, 1, 2, 5, 14, 42, 133, 442, 1535, 5546, 20754, 80113, 317875, 1292648, 5374073, 22794182, 98462847, 432498659, 1929221610, 8728815103, 40017844229, 185727603829, 871897549029, 4137132922197, 19828476952117, 95934298966615, 468291607852143, 2305162065138433
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OFFSET

0,3


COMMENTS

It appears that no formula or g.f. is known.


LINKS

Liang Chengwei, Shi Lecun and Cai Zhongyu, Table of n, a(n) for n = 0..500 (terms 0..74 from Andrew Conway and Miles Conway)
Andrew R. Conway, Miles Conway, Andrew Elvey Price and Anthony J. Guttmann, Patternavoiding ascent sequences of length 3, arXiv:2111.01279 [math.CO], Nov 01 2021.
Paul Duncan and Einar Steingrimsson, Pattern avoidance in ascent sequences, arXiv preprint arXiv:1109.3641 [math.CO], 2011.


CROSSREFS

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.
Sequence in context: A061815 A340361 A308329 * A346660 A129086 A035052
Adjacent sequences: A202058 A202059 A202060 * A202062 A202063 A202064


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Dec 10 2011


EXTENSIONS

More terms from Anthony Guttmann, Nov 04 2021


STATUS

approved



