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!)
A258557 Number of (4+1) X (n+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. 1
228, 652, 1244, 1891, 2509, 3314, 4313, 5356, 6331, 7470, 8820, 10231, 11591, 13132, 14901, 16748, 18561, 20572, 22828, 25179, 27513, 30062, 32873, 35796, 38719, 41874, 45308, 48871, 52451, 56280, 60405, 64676, 68981, 73552, 78436, 83483, 88581, 93962 (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) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-4) - 3*a(n-5) + 3*a(n-6) - a(n-7) for n>11.

Empirical g.f.: x*(228 - 32*x - 28*x^2 - 113*x^3 - 312*x^4 + 248*x^5 + 35*x^6 - 37*x^7 - 28*x^8 + 16*x^9 + 40*x^10) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Row 4 of A258554.

Sequence in context: A128808 A043411 A172531 * A206005 A228963 A252220

Adjacent sequences:  A258554 A258555 A258556 * A258558 A258559 A258560

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 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 September 16 08:18 EDT 2021. Contains 347469 sequences. (Running on oeis4.)