login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A227098 Number of n X n 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X(n+1) binary array having a sum of two, with rows and columns of the latter in lexicographically nondecreasing order 0
2, 15, 239, 8427, 754758, 180409504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Diagonal of A227103

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A212370 A302358 A192561 * A180610 A156750 A292798

Adjacent sequences:  A227095 A227096 A227097 * A227099 A227100 A227101

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 01 2013

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 December 5 10:11 EST 2021. Contains 349543 sequences. (Running on oeis4.)