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!)
A258553 Number of (n+1) X (7+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. 1
2008, 894, 2542, 4313, 8612, 13833, 21653, 31254, 43655, 57928, 75822, 96565, 121226, 148915, 181429, 218044, 259877, 306086, 358516, 416491, 481176, 551777, 630187, 715778, 809763, 911396, 1022618, 1142849, 1273350, 1413423, 1565057 (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*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>15.

Empirical g.f.: x*(2008 - 7138*x + 11014*x^2 - 8523*x^3 + 3036*x^4 + 3127*x^5 - 7731*x^6 + 6028*x^7 - 3207*x^8 + 2064*x^9 - 606*x^10 - 26*x^11 + 4*x^12 - 12*x^13 + 10*x^14) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 7 of A258554.

Sequence in context: A250922 A201343 A219083 * A258560 A281987 A172735

Adjacent sequences:  A258550 A258551 A258552 * A258554 A258555 A258556

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 20 11:50 EDT 2021. Contains 347586 sequences. (Running on oeis4.)