OFFSET
1,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..465
Juan S. Auli, Pattern Avoidance in Inversion Sequences, Ph. D. thesis, Dartmouth College, ProQuest Dissertations Publishing (2020), 27964164.
Juan S. Auli, Sergi Elizalde, Consecutive Patterns in Inversion Sequences, arXiv:1904.02694 [math.CO], 2019. See Table 1.
Andrew M. Baxter and Lara K. Pudwell, Enumeration schemes for vincular patterns, arXiv preprint arXiv:1108.2642 [math.CO], 2011-2012.
FORMULA
a(n) ~ c * d^n * n! * n^alfa, where d = 1/A240885 = 1/(sqrt(2) * InverseErf(sqrt(2/Pi))), alfa = 0.96094544076267076286993824810734... and c = 0.5103992709959036090170192609... - Vaclav Kotesovec, Oct 17 2019
MATHEMATICA
i120[1] = 1; i120[2] = 2; i120[n_] := i120[n] = Sum[s120[n, k], {k, 0, n - 1}]; s120[n_, k_] := s120[n, k] = i120[n - 1] - Sum[(n - 2 - j)*s120[n - 2, j], {j, k + 1, n - 2}]; Table[i120[m], {m, 1, 25}] (* Vaclav Kotesovec, Oct 17 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 17 2011
EXTENSIONS
a(11)-a(15) from Lars Blomberg, Apr 16 2018
a(16)-a(22) from Vaclav Kotesovec, Oct 17 2019
STATUS
approved