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!)
A252956 Number of (n+2) X (3+2) 0..4 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order. 1
223, 155, 259, 443, 871, 1681, 2999, 6103, 11983, 21749, 44515, 88087, 161123, 330817, 656011, 1210571, 2483599, 4939057, 9174815, 18819943, 37462903, 70101461, 143554507, 286165735, 538738571, 1101824353, 2197577587, 4162662491 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) - 2*a(n-2) - 3*a(n-3) - 13*a(n-4) + 8*a(n-5) + 70*a(n-6) - 105*a(n-7) + 42*a(n-8) for n>10.

Empirical g.f.: x*(223 - 737*x + 85*x^2 + 386*x^3 + 2981*x^4 + 91*x^5 - 14137*x^6 + 16334*x^7 - 4830*x^8 - 420*x^9) / ((1 - x)^2*(1 - 2*x)*(1 - 3*x^2)*(1 - 7*x^3)). - Colin Barker, Dec 07 2018

EXAMPLE

Some solutions for n=2:

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

..3..0..0..1..1....3..0..0..4..4....0..2..0..0..2....3..0..0..1..1

..2..4..4..0..4....2..3..3..1..1....0..0..2..0..0....2..3..3..0..0

..1..3..3..4..3....4..2..2..0..0....0..1..1..0..1....1..4..4..3..3

CROSSREFS

Column 3 of A252961.

Sequence in context: A268017 A267978 A234623 * A163653 A178551 A105982

Adjacent sequences:  A252953 A252954 A252955 * A252957 A252958 A252959

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 25 2014

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 5 18:32 EST 2021. Contains 349557 sequences. (Running on oeis4.)