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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A297860 Number of n X 2 0..1 arrays with every element equal to 2, 3 or 4 king-move adjacent elements, with upper left element zero. 4
0, 1, 2, 5, 10, 25, 54, 125, 282, 641, 1454, 3301, 7490, 17001, 38582, 87565, 198730, 451025, 1023614, 2323125, 5272402, 11965881, 27156934, 61633501, 139879130, 317460001, 720485262, 1635163525, 3711054050, 8422351625, 19114786774 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Column 2 of A297866.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-2) + 4*a(n-3) + 2*a(n-4).

Empirical g.f.: x^2*(1 + 2*x + 2*x^2) / ((1 + x)*(1 - x - 2*x^2 - 2*x^3)). - Colin Barker, Feb 21 2018

EXAMPLE

Some solutions for n=7:

..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0

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

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

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

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

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

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

CROSSREFS

Cf. A297866.

Sequence in context: A018356 A026383 A162963 * A002094 A212709 A264867

Adjacent sequences:  A297857 A297858 A297859 * A297861 A297862 A297863

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 07 2018

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 July 8 00:40 EDT 2020. Contains 335502 sequences. (Running on oeis4.)