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!)
A218079 Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..1 n X 3 array. 1
4, 8, 26, 78, 246, 762, 2370, 7372, 22916, 71264, 221580, 688986, 2142340, 6661388, 20712972, 64404986, 200261174, 622693012, 1936204472, 6020443090, 18719993212, 58208032550, 180992322576, 562778355430, 1749905592014, 5441164449786 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A218084.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 5*a(n-4) - a(n-5) for n>6.

Empirical g.f.: 2*x*(1 - x)*(2 + 2*x - x^2 - 4*x^3 - x^4) / (1 - 2*x - 4*x^2 + 5*x^4 + x^5). - Colin Barker, Jul 24 2018

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A218084.

Sequence in context: A126733 A297695 A333894 * A012982 A012952 A272588

Adjacent sequences:  A218076 A218077 A218078 * A218080 A218081 A218082

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 20 2012

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 18:16 EST 2021. Contains 349567 sequences. (Running on oeis4.)