The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A196690 Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,1,3,0,4 for x=0,1,2,3,4. 3
 2, 5, 11, 34, 101, 299, 890, 2643, 7855, 23340, 69355, 206087, 612384, 1819689, 5407175, 16067330, 47743801, 141869903, 421564034, 1252670447, 3722289195, 11060719828, 32866743207, 97662975451, 290203891328, 862335989181 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Every 0 is next to 0 2's, every 1 is next to 1 1's, every 2 is next to 2 3's, every 3 is next to 3 0's, every 4 is next to 4 4's. Column 2 of A196696. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - a(n-4) for n>5. Empirical g.f.: x*(2 + x - 5*x^2 - 3*x^3 + 2*x^4) / (1 - 2*x - 3*x^2 + x^4). - Colin Barker, Feb 22 2018 EXAMPLE Some solutions for n=4: ..0..0....0..0....0..0....0..1....1..1....0..0....0..0....1..1....1..1....0..0 ..0..3....1..1....0..3....0..1....0..0....0..0....3..0....0..0....0..0....0..0 ..0..0....0..0....3..0....0..0....0..0....0..3....0..0....0..1....3..0....1..0 ..1..1....0..0....0..0....1..1....1..1....0..0....0..0....0..1....0..0....1..0 CROSSREFS Cf. A196696. Sequence in context: A226919 A307316 A298122 * A101834 A117758 A284251 Adjacent sequences: A196687 A196688 A196689 * A196691 A196692 A196693 KEYWORD nonn AUTHOR R. H. Hardin, Oct 05 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 May 24 12:09 EDT 2024. Contains 372773 sequences. (Running on oeis4.)