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 A279554 Number of length n inversion sequences avoiding the patterns 010, 101, 120, 201, and 210. 22
 1, 1, 2, 5, 15, 51, 188, 733, 2979, 12495, 53708, 235396, 1048168, 4728757, 21569339, 99309057, 460932778, 2154402107 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS A length n inversion sequence e_1e_2...e_n is a sequence of integers where 0 <= e_i <= i-1. The term a(n) counts those length n inversion sequences with no entries e_i, e_j, e_k (where i e_j <> e_k and e_i >= e_k. This is the same as the set of length n inversion sequences avoiding 010, 101, 120, 201, and 210. LINKS Megan A. Martinez, Carla D. Savage, Patterns in Inversion Sequences II: Inversion Sequences Avoiding Triples of Relations, arXiv:1609.08106 [math.CO], 2016-2018. EXAMPLE The length 3 inversion sequences are 000, 001, 002, 011, 012. The length 4 inversion sequences are 0000, 0001, 0002, 0003, 0011, 0012, 0013, 0021, 0022, 0023, 0111, 0112, 0113, 0122, 0123. CROSSREFS Cf. A263777, A263778, A263779, A263780, A279551, A279552, A279553, A279555, A279556, A279557, A279558, A279559, A279560, A279561, A279562, A279563, A279564, A279565, A279566, A279567, A279568, A279569, A279570, A279571, A279572, A279573. Sequence in context: A073525 A007317 A181768 * A279555 A153197 A299968 Adjacent sequences:  A279551 A279552 A279553 * A279555 A279556 A279557 KEYWORD nonn,more AUTHOR Megan A. Martinez, Dec 15 2016 EXTENSIONS a(10)-a(11) from Alois P. Heinz, Feb 24 2017 a(12)-a(17) from Bert Dobbelaere, Dec 30 2018 STATUS approved

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Last modified January 24 10:24 EST 2020. Contains 331193 sequences. (Running on oeis4.)