login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A258547 Number of (n+1)X(1+1) 0..1 arrays with every 2X2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically 2
16, 44, 104, 228, 480, 988, 2008, 4052, 8144, 16332, 32712, 65476, 131008, 262076, 524216, 1048500, 2097072, 4194220, 8388520, 16777124, 33554336, 67108764, 134217624, 268435348, 536870800, 1073741708, 2147483528, 4294967172 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 and row 1 of A258554

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3)

a(n) = 16*2^n - 4*n - 12. - Michael Somos, Oct 14 2020

EXAMPLE

Some solutions for n=4

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

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

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

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

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

PROG

(PARI) {a(n) = if(n<-2, 0, 16*2^n - 4*n - 12)}; /* Michael Somos, Oct 14 2020 */

CROSSREFS

Cf. A258554

Sequence in context: A210375 A173560 A293858 * A211573 A211582 A204032

Adjacent sequences:  A258544 A258545 A258546 * A258548 A258549 A258550

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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 19 23:59 EDT 2022. Contains 356231 sequences. (Running on oeis4.)