A231382 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A231382

T(n,k)=Number of nXk 0..1 arrays with no element less than a strict majority of its horizontal and vertical neighbors

2, 2, 2, 4, 10, 4, 7, 21, 21, 7, 12, 48, 93, 48, 12, 21, 113, 378, 378, 113, 21, 37, 261, 1519, 2539, 1519, 261, 37, 65, 601, 6126, 17363, 17363, 6126, 601, 65, 114, 1390, 24747, 120124, 209118, 120124, 24747, 1390, 114, 200, 3216, 99964, 830890, 2547810

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Table starts

...2....2.......4.........7..........12.............21...............37

...2...10......21........48.........113............261..............601

...4...21......93.......378........1519...........6126............24747

...7...48.....378......2539.......17363.........120124...........830890

..12..113....1519.....17363......209118........2547810.........30936914

..21..261....6126....120124.....2547810.......54485279.......1157805351

..37..601...24747....830890....30936914.....1157805351......42978519280

..65.1390...99964...5746499...375620622....24615811883....1597438228604

.114.3216..403743..39745115..4560995236...523548909308...59402875813957

.200.7435.1630662.274872588.55375119088.11133382117666.2208383979206654

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..312

FORMULA

Empirical for column k:

k=1: a(n) = 2*a(n-1) -a(n-2) +a(n-3) for n>4

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

k=3: [order 10] for n>11

k=4: [order 19] for n>20

k=5: [order 46] for n>47

EXAMPLE

Some solutions for n=3 k=4

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

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

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

CROSSREFS

Column 1 is A005251(n+2)

Sequence in context: A153986 A199889 A293177 * A360314 A213270 A307522

Adjacent sequences: A231379 A231380 A231381 * A231383 A231384 A231385

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Nov 08 2013

STATUS

approved