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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A183877 Number of arrangements of n+2 numbers in 0..2 with each number being the sum mod 3 of two others. 1
 1, 31, 171, 631, 2059, 6399, 19483, 58807, 176859, 531103, 1593931, 4782519, 14348395, 43046143, 129139515, 387419767, 1162260667, 3486783519, 10460352235, 31381058551, 94143177675, 282429535231, 847288608091, 2541865826871 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical (for n>=2): 3^(n+2) - 2*(n+3)^2. - Vaclav Kotesovec, Nov 27 2012 Conjectures from Colin Barker, Apr 05 2018: (Start) G.f.: x*(1 + 25*x - 3*x^2 - 33*x^3 + 18*x^4) / ((1 - x)^3*(1 - 3*x)). a(n) = 6*a(n-1) - 12*a(n-2) + 10*a(n-3) - 3*a(n-4) for n>5. (End) Conjecture is true. The complement consists of arrangements of the forms 1*, 2*, 01*, 02*, 10*, 12*, 20*, 21*, 001*, 002* and 120*. Robert Israel, Sep 30 2018 EXAMPLE Some solutions for n=4: ..2....1....1....2....1....2....2....2....0....1....2....1....2....1....0....2 ..2....0....2....1....0....2....0....2....2....0....1....1....2....0....1....1 ..1....0....2....0....0....1....0....1....1....0....1....2....0....0....1....0 ..1....2....2....0....2....1....0....0....2....2....0....1....1....2....1....1 ..1....1....1....2....2....1....0....0....0....2....0....2....0....0....2....1 ..2....2....1....1....2....0....2....0....0....1....1....0....0....1....0....2 MAPLE 1, seq(3^(n+2)-2*(n+3)^2, n=2..30); # Robert Israel, Sep 30 2018 CROSSREFS Column 2 of A183884. Sequence in context: A184497 A184489 A140540 * A107953 A085249 A272130 Adjacent sequences: A183874 A183875 A183876 * A183878 A183879 A183880 KEYWORD nonn AUTHOR R. H. Hardin, Jan 07 2011 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 March 22 22:37 EDT 2023. Contains 361434 sequences. (Running on oeis4.)