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

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!)
 A234381 Number of (1+2) X (n+2) 0..2 arrays with no increasing sequence of length 3 horizontally or diagonally downwards. 1
 16584, 406416, 9995040, 245837376, 6045322368, 148657436928, 3655605662208, 89894348448768, 2210574247446528, 54359793423323136, 1336750972483608576, 32871779997322199040, 808343468249908543488, 19877815029157007523840 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 24*a(n-1) - 12*a(n-2) + 624*a(n-3) + 1056*a(n-4) - 8448*a(n-5) - 9216*a(n-6). Empirical g.f.: 24*x*(691 + 350*x + 18336*x^2 + 20208*x^3 - 247936*x^4 - 259584*x^5) / (1 - 24*x + 12*x^2 - 624*x^3 - 1056*x^4 + 8448*x^5 + 9216*x^6). - Colin Barker, Oct 14 2018 EXAMPLE Some solutions for n=1:   2 2 1   2 1 2   0 2 1   1 0 0   0 2 2   1 0 2   0 1 0   1 0 1   2 0 2   0 0 0   0 0 0   1 2 0   0 2 1   0 1 2   0 2 0   0 2 0   0 2 0   1 1 2   1 2 2   0 1 0   0 0 0 CROSSREFS Row 1 of A234380. Sequence in context: A344242 A234374 A234380 * A236638 A250930 A210272 Adjacent sequences:  A234378 A234379 A234380 * A234382 A234383 A234384 KEYWORD nonn AUTHOR R. H. Hardin, Dec 25 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.

Last modified December 5 06:52 EST 2021. Contains 349543 sequences. (Running on oeis4.)