This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A237853 Number of (n+1) X (2+1) 0..1 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors. 1
 4, 14, 41, 114, 325, 943, 2731, 7876, 22702, 65489, 188972, 545229, 1572979, 4538047, 13092532, 37772848, 108976855, 314404070, 907073003, 2616956517, 7550066383, 21782363122, 62843332744, 181306523557, 523079446954, 1509113417351 (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) - 2*a(n-2) + 4*a(n-3) + 2*a(n-4) + a(n-5). Empirical g.f.: x*(4 + 2*x + 7*x^2 + 3*x^3 + x^4) / (1 - 3*x + 2*x^2 - 4*x^3 - 2*x^4 - x^5). - Colin Barker, Oct 24 2018 EXAMPLE Some solutions for n=5: ..1..1..1....0..0..0....0..1..1....1..1..0....0..1..1....1..1..0....1..1..0 ..0..1..1....0..0..0....0..1..1....1..1..0....0..1..1....0..0..0....1..1..0 ..0..0..0....0..1..1....0..1..1....1..1..1....0..0..0....0..0..0....1..1..1 ..0..0..0....1..1..0....0..1..1....1..1..1....0..0..0....1..1..1....0..0..0 ..1..1..1....0..0..0....0..1..1....0..1..1....0..0..0....0..1..1....0..0..0 ..1..1..1....0..0..0....0..1..1....0..1..1....1..1..0....0..1..1....0..0..0 CROSSREFS Column 2 of A237859. Sequence in context: A326008 A196713 A261547 * A132357 A262875 A219867 Adjacent sequences:  A237850 A237851 A237852 * A237854 A237855 A237856 KEYWORD nonn AUTHOR R. H. Hardin, Feb 14 2014 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 15 09:05 EST 2019. Contains 329995 sequences. (Running on oeis4.)