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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A240342 Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or three plus the sum of the elements diagonally to its northwest, modulo 4. 1
 4, 18, 78, 334, 1418, 6002, 25374, 107230, 453098, 1914498, 8089374, 34180206, 144422410, 610231506, 2578426334, 10894689470, 46033605738, 194506954850, 821855141726, 3472605259214, 14672886589706, 61997717795634 (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) = 6*a(n-1) - 7*a(n-2) - 4*a(n-3) + 8*a(n-4). Empirical g.f.: 2*x*(1 + x)*(2 - 5*x + 4*x^2) / (1 - 6*x + 7*x^2 + 4*x^3 - 8*x^4). - Colin Barker, Oct 27 2018 EXAMPLE Some solutions for n=4: ..2..2....2..0....0..0....2..2....0..2....2..2....2..2....0..2....0..0....2..0 ..2..0....0..2....0..2....0..0....0..2....2..0....2..0....2..2....2..2....2..0 ..0..0....0..2....2..2....2..2....0..0....2..0....0..0....2..2....0..0....0..2 ..0..2....2..0....2..2....0..2....0..0....0..0....2..1....2..2....0..2....0..0 CROSSREFS Column 2 of A240347. Sequence in context: A058870 A219436 A219137 * A208309 A112619 A196810 Adjacent sequences:  A240339 A240340 A240341 * A240343 A240344 A240345 KEYWORD nonn AUTHOR R. H. Hardin, Apr 04 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 May 11 21:35 EDT 2021. Contains 343808 sequences. (Running on oeis4.)