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!)
 A183315 Number of n X 3 binary arrays with an element zero only if there are an even number of ones to its left and an even number of ones above it. 1
 5, 13, 43, 124, 377, 1109, 3305, 9767, 28959, 85677, 253693, 750777, 2222308, 6577131, 19466625, 57614249, 170519517, 504678557, 1493676557, 4420766649, 13083945331, 38723960052, 114609540289, 339204648201, 1003928499625 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A183322. LINKS R. H. Hardin, Table of n, a(n) for n = 1..200 FORMULA Empirical: a(n) = a(n-1) + 9*a(n-2) - 3*a(n-3) - 21*a(n-4) + a(n-5) + 13*a(n-6) + a(n-7) - a(n-8). Empirical g.f.: x*(5 + 8*x - 15*x^2 - 21*x^3 + 10*x^4 + 13*x^5 - x^7) / (1 - x - 9*x^2 + 3*x^3 + 21*x^4 - x^5 - 13*x^6 - x^7 + x^8). - Colin Barker, Mar 27 2018 EXAMPLE Some solutions for 5 X 3: ..1..1..1....0..1..1....1..1..0....1..1..0....1..1..0....1..1..1....1..1..0 ..1..1..1....1..1..1....1..1..0....1..1..0....1..1..1....1..1..1....1..1..1 ..0..0..0....1..1..1....0..0..0....0..1..1....1..1..1....0..0..0....0..0..1 ..0..1..1....0..1..1....0..0..0....0..1..1....1..1..0....1..1..0....0..0..1 ..0..1..1....0..0..1....0..1..1....0..0..1....1..1..0....1..1..1....0..1..1 CROSSREFS Cf. A183322. Sequence in context: A093576 A147259 A328740 * A183184 A115785 A218926 Adjacent sequences:  A183312 A183313 A183314 * A183316 A183317 A183318 KEYWORD nonn AUTHOR R. H. Hardin, Jan 03 2011 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 June 17 00:17 EDT 2021. Contains 345080 sequences. (Running on oeis4.)