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!)
A253526 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock antidiagonal maximum minus diagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal minimum nondecreasing vertically. 1
81, 459, 1963, 7253, 25165, 85663, 291511, 997121, 3427953, 11826315, 40885971, 141512469, 490082653, 1697732055, 5882051383, 20380576545, 70618256025, 244694019755, 847876017411, 2937937280013, 10180127318973, 35274764991959 (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) = 8*a(n-1) - 22*a(n-2) + 21*a(n-3) + 13*a(n-4) - 46*a(n-5) + 40*a(n-6) - 15*a(n-7) + 2*a(n-8).

Empirical g.f.: x*(81 - 189*x + 73*x^2 - 54*x^3 - 365*x^4 + 445*x^5 - 121*x^6 + 18*x^7) / ((1 - x)^4*(1 - 4*x + 7*x^3 - 2*x^4)). - Colin Barker, Dec 17 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 1 of A253533.

Sequence in context: A236664 A253533 A183971 * A183963 A236354 A236349

Adjacent sequences:  A253523 A253524 A253525 * A253527 A253528 A253529

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 03 2015

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 October 26 08:00 EDT 2021. Contains 348267 sequences. (Running on oeis4.)