login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A253504 Number of (n+2) X (2+2) 0..1 arrays with every 2 X 2 and 3X3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically. 1
260, 472, 784, 1196, 1712, 2340, 3088, 3964, 4976, 6132, 7440, 8908, 10544, 12356, 14352, 16540, 18928, 21524, 24336, 27372, 30640, 34148, 37904, 41916, 46192, 50740, 55568, 60684, 66096, 71812, 77840, 84188, 90864, 97876, 105232, 112940, 121008 (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) = (4/3)*n^3 + 36*n^2 + (332/3)*n + 92 for n>2.

Conjectures from Colin Barker, Dec 16 2018: (Start)

G.f.: 4*x*(65 - 142*x + 114*x^2 - 37*x^3 + x^4 + x^5) / (1 - x)^4.

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>6.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 2 of A253510.

Sequence in context: A252248 A214471 A139408 * A154379 A185793 A237631

Adjacent sequences:  A253501 A253502 A253503 * A253505 A253506 A253507

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 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 November 13 12:45 EST 2019. Contains 329094 sequences. (Running on oeis4.)