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!)
A250512 Number of (n+1)X(1+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. 1
120, 889, 5996, 39187, 248942, 1555689, 9605300, 58826247, 358185874, 2172028005, 13132419904, 79233189251, 477317759278, 2872297644737, 17270479247100, 103783325757983, 623401528654314, 3743476771002397, 22474273340351352 (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) = 10*a(n-1) - 15*a(n-2) - 80*a(n-3) + 122*a(n-4) + 228*a(n-5) - 120*a(n-6) - 144*a(n-7).

Empirical g.f.: x*(120 - 311*x - 1094*x^2 + 2162*x^3 + 3492*x^4 - 2064*x^5 - 2304*x^6) / ((1 - x)*(1 + 2*x)*(1 - 6*x)*(1 - 2*x - 2*x^2)*(1 - 3*x - 6*x^2)). - Colin Barker, Nov 14 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 1 of A250519.

Sequence in context: A029573 A211471 A250519 * A011245 A213875 A092182

Adjacent sequences:  A250509 A250510 A250511 * A250513 A250514 A250515

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 24 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 6 13:24 EST 2021. Contains 349563 sequences. (Running on oeis4.)