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!)
A297315 Number of 2 X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 or 2 neighboring 1s. 1
1, 7, 23, 66, 207, 654, 2049, 6422, 20119, 63033, 197551, 619096, 1940007, 6079365, 19051015, 59700283, 187082905, 586262278, 1837172149, 5757153010, 18041210871, 56535805498, 177166451873, 555187134041, 1739791875173, 5451991915452 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 8*a(n-3) - 3*a(n-4) + 7*a(n-5) - 5*a(n-6) - a(n-7) - a(n-8) + a(n-9).

Empirical g.f.: x*(1 + x - x^2)*(1 + 3*x + 2*x^2 + 4*x^3 - x^5 - x^6) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 2*x^2 - 5*x^3 + x^5 + x^6)). - Colin Barker, Feb 26 2019

EXAMPLE

Some solutions for n=5:

..1..1..0..1..0. .0..0..0..1..1. .1..1..0..0..0. .0..0..0..1..0

..0..1..1..0..0. .1..1..1..0..0. .0..1..1..1..0. .0..0..1..0..0

CROSSREFS

Row 2 of A297314.

Sequence in context: A066187 A259214 A114246 * A048457 A048458 A134350

Adjacent sequences:  A297312 A297313 A297314 * A297316 A297317 A297318

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2017

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 2 04:43 EST 2021. Contains 349437 sequences. (Running on oeis4.)