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!)
A240316 Number of n X 2 0..3 arrays with no element equal to two plus the sum of elements to its left or two plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4. 1
2, 4, 18, 44, 184, 444, 1826, 4388, 18022, 43300, 177856, 427348, 1755406, 4217900, 17325794, 41630540, 171004968, 410891868, 1687812450, 4055486788, 16658643286, 40027496964, 164420161936, 395069839924, 1622820610830, 3899323972492 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 12*a(n-2) - 24*a(n-4) + 31*a(n-6) - 16*a(n-8).
Empirical g.f.: 2*x*(1 + 2*x - 3*x^2 - 2*x^3 + 8*x^4 + 6*x^5 - 6*x^6 - 4*x^7) / (1 - 12*x^2 + 24*x^4 - 31*x^6 + 16*x^8). - Colin Barker, Oct 27 2018
EXAMPLE
Some solutions for n=4:
..3..3....1..1....1..1....1..1....3..3....1..1....1..1....1..1....3..3....1..1
..3..0....1..2....1..0....1..0....3..2....1..0....1..2....1..2....3..2....1..0
..3..0....1..2....3..2....1..0....1..1....1..0....3..2....3..2....3..0....3..0
..1..2....3..0....1..2....3..0....3..3....3..2....1..1....1..2....1..0....1..2
CROSSREFS
Column 2 of A240321.
Sequence in context: A143533 A064723 A301620 * A151449 A045664 A106520
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 03 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)