A259509 - OEIS

A259509

Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0001 0101 0111.

31, 129, 533, 2219, 9227, 38409, 159845, 665339, 2769251, 11526489, 47976173, 199690619, 831166667, 3459548649, 14399597045, 59935131419, 249466635731, 1038349453209, 4321898626973, 17988942330779, 74874972302267

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OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 2*a(n-1) + 11*a(n-2) - 4*a(n-3) - 18*a(n-4).

Empirical g.f.: x*(31 + 67*x - 66*x^2 - 142*x^3) / ((1 - 2*x^2)*(1 - 2*x - 9*x^2)). - Colin Barker, Dec 25 2018

EXAMPLE

Some solutions for n=4:

..1..0..0....1..0..0....0..1..0....0..0..0....0..0..1....1..0..1....0..0..0

..1..1..0....0..0..1....1..0..1....1..0..1....0..1..1....0..1..0....0..1..0

..1..0..0....0..0..0....1..1..1....0..1..0....0..0..1....1..0..1....0..0..1

..0..1..0....1..0..0....1..0..1....1..0..1....0..0..0....1..1..0....0..1..1

..1..1..1....1..1..0....1..1..1....1..1..0....1..0..1....1..0..1....0..0..1

CROSSREFS

Column 2 of A259515.

Sequence in context: A065403 A278054 A035502 * A183838 A043355 A023728

Adjacent sequences: A259506 A259507 A259508 * A259510 A259511 A259512

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 29 2015

STATUS

approved