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!)
A251403 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock summing to a prime. 1
46, 238, 1230, 6370, 32954, 170634, 883018, 4571514, 23660362, 122482746, 633962570, 3281695226, 16986365322, 87927675962, 455129029834, 2355889539450, 12194590587914, 63122652320442, 326737675994954, 1691282074795002 (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) = 2*a(n-1) + 21*a(n-2) - 14*a(n-3) - 52*a(n-4) + 12*a(n-5).

Empirical g.f.: 2*x*(23 + 73*x - 106*x^2 - 222*x^3 + 54*x^4) / (1 - 2*x - 21*x^2 + 14*x^3 + 52*x^4 - 12*x^5). - Colin Barker, Nov 29 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 1 of A251410.

Sequence in context: A234161 A234154 A251410 * A026913 A244744 A156841

Adjacent sequences:  A251400 A251401 A251402 * A251404 A251405 A251406

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 02 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 April 3 14:34 EDT 2020. Contains 333197 sequences. (Running on oeis4.)