A183838 - OEIS

A183838

Number of (n+1) X 3 binary arrays with each element of every 2 X 2 subblock being the sum mod 2 of two others.

31, 129, 542, 2297, 9747, 41430, 176119, 748937, 3184790, 13544009, 57598363, 244951310, 1041712935, 4430144161, 18840275454, 80122960441, 340742738947, 1449093190086, 6162628517847, 26208108810425, 111456491689126

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OFFSET

1,1

COMMENTS

Column 2 of A183845.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 5*a(n-1) + a(n-2) - 22*a(n-3) + 18*a(n-4).

Empirical g.f.: x*(31 - 26*x - 134*x^2 + 140*x^3) / (1 - 5*x - x^2 + 22*x^3 - 18*x^4). - Colin Barker, Apr 05 2018

EXAMPLE

Some solutions for 5 X 3:

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

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

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

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

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

CROSSREFS

Cf. A183845.

Sequence in context: A278054 A035502 A259509 * A043355 A023728 A045259

Adjacent sequences: A183835 A183836 A183837 * A183839 A183840 A183841

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 07 2011

STATUS

approved