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A301491 T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 1, 2, 4, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 7
1, 2, 2, 4, 7, 4, 8, 18, 18, 8, 16, 50, 52, 50, 16, 32, 138, 148, 148, 138, 32, 64, 383, 441, 599, 441, 383, 64, 128, 1063, 1372, 2354, 2354, 1372, 1063, 128, 256, 2951, 4326, 9415, 15124, 9415, 4326, 2951, 256, 512, 8193, 13641, 38558, 93753, 93753, 38558, 13641 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Table starts

...1....2.....4......8.......16........32..........64..........128

...2....7....18.....50......138.......383........1063.........2951

...4...18....52....148......441......1372........4326........13641

...8...50...148....599.....2354......9415.......38558.......158994

..16..138...441...2354....15124.....93753......594953......3838256

..32..383..1372...9415....93753....903707.....8479276.....81180752

..64.1063..4326..38558...594953...8479276...116648010...1642511178

.128.2951.13641.158994..3838256..81180752..1642511178..34593556316

.256.8193.42741.657238.24838061.782053062.23269383762.732289348979

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..199

FORMULA

Empirical for column k:

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

k=2: a(n) = 3*a(n-1) -a(n-2) +a(n-3) +a(n-4) -2*a(n-5) -a(n-6)

k=3: [order 24] for n>25

k=4: [order 89] for n>91

EXAMPLE

Some solutions for n=5 k=4

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

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

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

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

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

CROSSREFS

Column 1 is A000079(n-1).

Column 2 is A280598.

Sequence in context: A300498 A300937 A300881 * A208269 A184761 A270227

Adjacent sequences:  A301488 A301489 A301490 * A301492 A301493 A301494

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Mar 22 2018

STATUS

approved

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Last modified May 23 03:04 EDT 2019. Contains 323507 sequences. (Running on oeis4.)