The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A116711 Number of permutations of length n which avoid the patterns 123, 3214, 4312. 3
 1, 2, 5, 12, 23, 36, 51, 68, 87, 108, 131, 156, 183, 212, 243, 276, 311, 348, 387, 428, 471, 516, 563, 612, 663, 716, 771, 828, 887, 948, 1011, 1076, 1143, 1212, 1283, 1356, 1431, 1508, 1587, 1668, 1751, 1836, 1923, 2012, 2103, 2196, 2291, 2388, 2487, 2588 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005. Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA G.f.: x*(1 - x + 2*x^2 + 2*x^3 - 2*x^5) / (1 - x)^3. For n >= 4, a(n) = n^2 + 2*n - 12. - Franklin T. Adams-Watters, Sep 16 2006 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3. - Colin Barker, Oct 23 2017 PROG (PARI) Vec(x*(1 - x + 2*x^2 + 2*x^3 - 2*x^5) / (1 - x)^3 + O(x^50)) \\ Colin Barker, Oct 23 2017 CROSSREFS Sequence in context: A123647 A166249 A326762 * A247658 A109653 A115520 Adjacent sequences: A116708 A116709 A116710 * A116712 A116713 A116714 KEYWORD nonn,easy AUTHOR Lara Pudwell, Feb 26 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 13 14:18 EDT 2024. Contains 375142 sequences. (Running on oeis4.)