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!)
A252979 Number of n X 4 nonnegative integer arrays with upper left 0 and lower right its king-move distance away minus 2 and every value increasing by 0 or 1 with every step right, diagonally se or down. 1
3, 13, 33, 68, 1247, 8487, 27905, 62977, 114433, 182273, 266497, 367105, 484097, 617473, 767233, 933377, 1115905, 1314817, 1530113, 1761793, 2009857, 2274305, 2555137, 2852353, 3165953, 3495937, 3842305, 4205057, 4584193, 4979713, 5391617 (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) = 8192*n^2 - 87808*n + 241153 for n>6.

Conjectures from Colin Barker, Dec 08 2018: (Start)

G.f.: x*(3 + 4*x + 3*x^2 + 5*x^3 + 1129*x^4 + 4917*x^5 + 6117*x^6 + 3476*x^7 + 730*x^8) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>9.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 4 of A252983.

Sequence in context: A147137 A146230 A166805 * A332366 A033943 A026084

Adjacent sequences:  A252976 A252977 A252978 * A252980 A252981 A252982

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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 28 17:45 EDT 2022. Contains 357080 sequences. (Running on oeis4.)