A229521 T(n,k) = number of n X k 0..2 arrays of the median of the corresponding element, the element to the east and the element to the south in a larger (n+1) X (k+1) 0..2 array without adjacent equal elements in the latter.

3, 7, 7, 17, 33, 17, 39, 129, 129, 39, 91, 481, 775, 481, 91, 211, 1751, 4193, 4193, 1751, 211, 491, 6433, 23059, 34151, 23059, 6433, 491, 1141, 23507, 124431, 275243, 275243, 124431, 23507, 1141, 2653, 86295, 680991, 2223913, 3336437, 2223913, 680991

Offset

1,1

Comments

Table starts

....3......7.......17.........39..........91...........211.............491

....7.....33......129........481........1751..........6433...........23507

...17....129......775.......4193.......23059........124431..........680991

...39....481.....4193......34151......275243.......2223913........17910863

...91...1751....23059.....275243.....3336437......39543877.......476435051

..211...6433...124431....2223913....39543877.....701321971.....12425155219

..491..23507...680991...17910863...476435051...12425155219....329002027139

.1141..86295..3698901..144971845..5674074209..220821219009...8615734849077

.2653.316099.20206283.1169783337.68219097971.3914741097513.227806404072631

Links

R. H. Hardin, Table of n, a(n) for n = 1..179

Formula

Empirical for column k:

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

k=2: [order 20].

k=3: [order 44] for n > 45.

k=4: [order 75] for n > 77.

Example

Some solutions for n=3, k=4:
  2 0 1 1     2 0 1 1     1 0 1 1     2 0 2 1     1 0 1 1
  1 1 0 1     0 1 1 1     1 1 0 1     0 1 0 1     1 1 2 1
  1 1 2 0     1 0 1 2     1 0 1 1     1 0 1 1     1 1 1 2

Crossrefs

Sequence in context: A240260 A240427 A239047 * A263337 A160994 A113833

Adjacent sequences: A229518 A229519 A229520 * A229522 A229523 A229524

Keyword

nonn,tabl

Author

R. H. Hardin, Sep 25 2013

Status

approved