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

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!)
 A220373 Equals two maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and vertical neighbors in a random 0..2 nX3 array 1
 2, 23, 236, 2095, 18296, 154562, 1280878, 10492879, 85253117, 688997802, 5548695509, 44580367227, 357622113010, 2865892548630, 22950987106487, 183716756194773, 1470171909243331, 11762592622678971, 94098427741015878 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A220375 LINKS R. H. Hardin, Table of n, a(n) for n = 1..48 EXAMPLE Some solutions for n=3 ..1..1..0....1..1..0....1..0..1....1..1..0....0..1..1....1..0..0....0..1..1 ..1..1..1....1..1..0....0..0..1....1..0..0....0..0..1....0..1..1....1..0..1 ..0..0..1....0..0..0....1..1..0....0..0..0....1..0..0....0..0..1....1..1..0 CROSSREFS Sequence in context: A019518 A048677 A132933 * A220428 A110773 A088087 Adjacent sequences:  A220370 A220371 A220372 * A220374 A220375 A220376 KEYWORD nonn AUTHOR R. H. Hardin Dec 13 2012 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.

Last modified December 8 20:37 EST 2021. Contains 349596 sequences. (Running on oeis4.)