A227442 - OEIS

A227442

T(n,k) = Number of n X k 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X (k+1) binary array having two adjacent 1's and two adjacent 0's.

2, 4, 4, 8, 16, 8, 16, 62, 62, 16, 32, 240, 457, 240, 32, 64, 932, 3346, 3346, 932, 64, 128, 3620, 24568, 46126, 24568, 3620, 128, 256, 14056, 180575, 636996, 636996, 180575, 14056, 256, 512, 54576, 1327102, 8802600, 16517429, 8802600, 1327102, 54576, 512

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OFFSET

1,1

COMMENTS

Table starts

...2......4........8..........16...........32............64...........128

...4.....16.......62.........240..........932..........3620.........14056

...8.....62......457........3346........24568........180575.......1327102

..16....240.....3346.......46126.......636996.......8802600.....121623396

..32....932....24568......636996.....16517429.....428106288...11089818502

..64...3620...180575.....8802600....428106288...20779660903.1007348570226

.128..14056..1327102...121623396..11089818502.1007348570226

.256..54576..9752326..1680297950.287216470434

.512.211912.71665377.23214121178

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..84

FORMULA

Empirical for column k:

k=1: a(n) = 2*a(n-1).

k=2: a(n) = 4*a(n-1) -2*a(n-2) +6*a(n-3).

k=3: [order 9].

EXAMPLE

Some solutions for n=4, k=4

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

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

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

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

CROSSREFS

Column 1 is A000079.

Sequence in context: A297102 A283415 A283857 * A282316 A228986 A188910

Adjacent sequences: A227439 A227440 A227441 * A227443 A227444 A227445

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Jul 11 2013

STATUS

approved