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!)
A281696 Number of 4Xn 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 222, 19326, 402470, 7497214, 126719222, 1847808312, 25489973264, 335106626139, 4243531978116, 52250869377772, 628947105706014, 7431279191300006, 86458169278267534, 992830171072101269 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 4 of A281693.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..109

EXAMPLE

Some solutions for n=3

..0..1..2. .0..0..0. .0..0..1. .0..1..1. .0..1..2. .0..0..1. .0..1..1

..2..1..0. .1..1..2. .2..1..2. .1..0..0. .0..1..2. .1..0..2. .0..2..2

..2..0..0. .1..2..1. .1..0..0. .2..2..1. .1..1..0. .2..0..2. .2..1..1

..1..1..1. .1..2..0. .2..2..2. .1..0..0. .0..0..2. .1..2..1. .0..1..2

CROSSREFS

Cf. A281693.

Sequence in context: A043499 A251059 A220230 * A280311 A268024 A267931

Adjacent sequences:  A281693 A281694 A281695 * A281697 A281698 A281699

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 27 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 6 10:57 EST 2021. Contains 349563 sequences. (Running on oeis4.)