A374553 Number of length n inversion sequences avoiding the patterns 010 and 102.
1, 1, 2, 5, 15, 51, 186, 707, 2763, 11024, 44714, 183830, 764374, 3209031, 13584217, 57918257, 248502212, 1072159593, 4648747281, 20245772943, 88524364619, 388469248937, 1710304847176, 7552480937589, 33442335151831, 148456424569164, 660560252794208
Offset: 0
Keywords
Links
- Benjamin Testart, Table of n, a(n) for n = 0..700
- Jay Pantone, The enumeration of inversion sequences avoiding the patterns 201 and 210, arXiv:2310.19632 [math.CO], 2023.
- Benjamin Testart, Completing the enumeration of inversion sequences avoiding one or two patterns of length 3, arXiv:2407.07701 [math.CO], 2024.
- Benjamin Testart, Generating trees growing on the left for pattern-avoiding inversion sequences, arXiv:2411.05726 [math.CO], 2024.
Formula
G.f. F(x) is algebraic with minimal polynomial x * (x^2 - x + 1)*(x - 1)^2 * F(x)^3 + 2*x*(x - 1)*(2*x^2 - 2*x + 1)*F(x)^2 - (x^4 - 8*x^3 + 11*x^2 - 6*x + 1)*F(x) - (2*x - 1)*(x - 1)^2.