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!)
A281062 Number of 7Xn 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 1686, 15028, 27635, 58005, 119205, 221212, 394884, 689397, 1191475, 2050466, 3523654, 6051629, 10389370, 17827528, 30568529, 52364160, 89595493, 153099429, 261254732, 445190263, 757565887, 1287362382, 2184769552, 3703030677 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 7 of A281056.

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>20

EXAMPLE

Some solutions for n=4

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

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

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

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

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

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

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

CROSSREFS

Cf. A281056.

Sequence in context: A205515 A335338 A263061 * A020241 A065903 A204488

Adjacent sequences:  A281059 A281060 A281061 * A281063 A281064 A281065

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 13 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 3 05:05 EST 2021. Contains 349445 sequences. (Running on oeis4.)