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!)
 A259290 Number of (n+1) X (1+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0001 0101 or 0111. 1
 10, 26, 66, 170, 434, 1114, 2850, 7306, 18706, 47930, 122754, 314474, 805490, 2063386, 5285346, 13538890, 34680274, 88835834, 227556930, 582900266, 1493127986, 3824729050, 9797240994, 25096157194, 64285121170, 164669749946 (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) = a(n-1) + 4*a(n-2). Conjectures from Colin Barker, Dec 25 2018: (Start) G.f.: 2*x*(5 + 8*x) / (1 - x - 4*x^2). a(n) = (2^(1-n)*((1-sqrt(17))^n*(-4+sqrt(17)) + (1+sqrt(17))^n*(4+sqrt(17)))) / sqrt(17). (End) EXAMPLE Some solutions for n=4: ..1..0....1..0....1..0....1..0....1..1....1..0....1..0....0..0....0..1....1..1 ..1..1....0..1....0..1....1..1....0..1....0..0....0..1....1..0....1..0....0..1 ..0..1....1..1....1..0....1..0....0..0....1..0....1..1....0..0....1..1....1..1 ..0..0....0..1....0..0....1..1....1..0....0..0....0..1....0..1....0..1....1..0 ..1..0....1..1....0..1....1..0....0..0....1..0....0..0....1..0....1..1....0..0 CROSSREFS Column 1 of A259297. Sequence in context: A332596 A134420 A144255 * A072379 A005970 A192254 Adjacent sequences:  A259287 A259288 A259289 * A259291 A259292 A259293 KEYWORD nonn AUTHOR R. H. Hardin, Jun 23 2015 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 April 4 07:32 EDT 2020. Contains 333213 sequences. (Running on oeis4.)