login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A183644 Number of (n+1) X 2 0..4 arrays with every 2 X 2 subblock summing to 8. 1
85, 325, 1333, 5725, 25405, 115525, 535333, 2517805, 11982925, 57575125, 278766133, 1358125885, 6649985245, 32693825125, 161264049733, 797557733965, 3952911584365, 19625567713525, 97573430562133, 485654176126045 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A183652.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 15*a(n-1) - 85*a(n-2) + 225*a(n-3) - 274*a(n-4) + 120*a(n-5).

Conjectures from Colin Barker, Mar 31 2018: (Start)

G.f.: x*(85 - 950*x + 3683*x^2 - 5770*x^3 + 3000*x^4) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)).

a(n) = 2 + 2^(2+n) + 2^(3+2*n) + 2*3^(1+n) + 5^(1+n).

(End)

EXAMPLE

Some solutions for 3 X 2:

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

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

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

CROSSREFS

Cf. A183652.

Sequence in context: A020200 A020298 A183652 * A068559 A045017 A297399

Adjacent sequences:  A183641 A183642 A183643 * A183645 A183646 A183647

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 06 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 23 23:53 EDT 2022. Contains 353993 sequences. (Running on oeis4.)