OFFSET
0,3
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Darla Kremer and Wai Chee Shiu, Finite transition matrices for permutations avoiding pairs of length four patterns, Discrete Math. 268 (2003), 171-183. MR1983276 (2004b:05006). See Table 1.
Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.
Index entries for linear recurrences with constant coefficients, signature (7,-17,22,-13,4).
FORMULA
G.f.: (x^5-5*x^4+13*x^3-12*x^2+6*x-1) / (4*x^5-13*x^4+22*x^3-17*x^2+7*x-1). (corrected by Jay Pantone, Feb 18 2016)
a(n) = 7*a(n-1) - 17*a(n-2) + 22*a(n-3) - 13*a(n-4) + 4*a(n-5) for n>6. - Colin Barker, Oct 25 2017
PROG
(PARI) Vec((1 - 6*x + 12*x^2 - 13*x^3 + 5*x^4 - x^5) / (1 - 7*x + 17*x^2 - 22*x^3 + 13*x^4 - 4*x^5) + O(x^30)) \\ Colin Barker, Oct 25 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Lara Pudwell, Feb 26 2006
EXTENSIONS
Prepended a(0)=1 by Joerg Arndt, Feb 18 2016
STATUS
approved