login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A223408 4 X 4 X 4 triangular graph without horizontal edges coloring a rectangular array: number of n X 1 0..9 arrays where 0..9 label nodes of a graph with edges 0,1 0,2 1,3 1,4 2,4 2,5 3,6 3,7 4,7 4,8 5,8 5,9 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph. 1
10, 24, 66, 176, 486, 1312, 3622, 9792, 27030, 73088, 201750, 545536, 1505878, 4071936, 11240022, 30393344, 83896662, 226859008, 626213206, 1693298688, 4674118998, 12638953472, 34888099158, 94338433024, 260408317270 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A223415.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 9*a(n-2) - 12*a(n-4) + 4*a(n-6).

Empirical g.f.: 2*x*(5 + 12*x - 12*x^2 - 20*x^3 + 6*x^4 + 8*x^5) / ((1 - x)*(1 + x)*(1 + 2*x - 2*x^2)*(1 - 2*x - 2*x^2)). - Colin Barker, Aug 20 2018

EXAMPLE

Some solutions for n=3:

..1....7....4....4....8....2....5....4....1....2....4....4....3....4....1....6

..4....4....7....8....4....0....2....2....0....4....8....1....6....2....4....3

..1....8....3....5....7....1....4....0....1....8....4....0....3....5....2....1

CROSSREFS

Cf. A223415.

Sequence in context: A250798 A250576 A126911 * A261807 A135285 A235940

Adjacent sequences:  A223405 A223406 A223407 * A223409 A223410 A223411

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 20 2013

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 8 05:44 EST 2021. Contains 349590 sequences. (Running on oeis4.)