OFFSET
1,2
LINKS
D. Callan, T. Mansour, Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns, arXiv:1705.00933 [math.CO] (2017), Table 2 No 100 and 101.
Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.
Index entries for linear recurrences with constant coefficients, signature (8,-26,47,-52,35,-13,2).
FORMULA
G.f.: A(x) = -{(x^2-x+1)(2x^4-7x^3+10x^2-5x+1)x}/{(2x^4-7x^3+8x^2-5x+1)(x-1)^3}
MATHEMATICA
LinearRecurrence[{8, -26, 47, -52, 35, -13, 2}, {1, 2, 6, 21, 73, 242, 772}, 30] (* Harvey P. Dale, Sep 07 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Lara Pudwell, Feb 26 2006
STATUS
approved