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”).
%I #8 Apr 27 2021 20:57:50
%S 3,7,7,17,33,17,39,129,129,39,91,481,775,481,91,211,1751,4193,4193,
%T 1751,211,491,6433,23059,34151,23059,6433,491,1141,23507,124431,
%U 275243,275243,124431,23507,1141,2653,86295,680991,2223913,3336437,2223913,680991
%N 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.
%C Table starts
%C ....3......7.......17.........39..........91...........211.............491
%C ....7.....33......129........481........1751..........6433...........23507
%C ...17....129......775.......4193.......23059........124431..........680991
%C ...39....481.....4193......34151......275243.......2223913........17910863
%C ...91...1751....23059.....275243.....3336437......39543877.......476435051
%C ..211...6433...124431....2223913....39543877.....701321971.....12425155219
%C ..491..23507...680991...17910863...476435051...12425155219....329002027139
%C .1141..86295..3698901..144971845..5674074209..220821219009...8615734849077
%C .2653.316099.20206283.1169783337.68219097971.3914741097513.227806404072631
%H R. H. Hardin, <a href="/A229521/b229521.txt">Table of n, a(n) for n = 1..179</a>
%F Empirical for column k:
%F k=1: a(n) = 2*a(n-1) + a(n-2) - a(n-3) + a(n-4).
%F k=2: [order 20].
%F k=3: [order 44] for n > 45.
%F k=4: [order 75] for n > 77.
%e Some solutions for n=3, k=4:
%e 2 0 1 1 2 0 1 1 1 0 1 1 2 0 2 1 1 0 1 1
%e 1 1 0 1 0 1 1 1 1 1 0 1 0 1 0 1 1 1 2 1
%e 1 1 2 0 1 0 1 2 1 0 1 1 1 0 1 1 1 1 1 2
%K nonn,tabl
%O 1,1
%A _R. H. Hardin_, Sep 25 2013