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 A250587 Number of (n+1)X(3+1) 0..2 arrays with nondecreasing max(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction 1

%I

%S 639,3641,17718,79415,333355,1347397,5284985,20355558,77281643,

%T 290814703,1086782674,4044122800,14999512012,55523390718,205218626587,

%U 757840894067,2796700223479,10316975388347,38048035207739,140296439330149

%N Number of (n+1)X(3+1) 0..2 arrays with nondecreasing max(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction

%C Column 3 of A250592

%H R. H. Hardin, <a href="/A250587/b250587.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 13*a(n-1) -54*a(n-2) -4*a(n-3) +674*a(n-4) -1673*a(n-5) -904*a(n-6) +9791*a(n-7) -10723*a(n-8) -16532*a(n-9) +44343*a(n-10) -9985*a(n-11) -62272*a(n-12) +59755*a(n-13) +25323*a(n-14) -65551*a(n-15) +16714*a(n-16) +28793*a(n-17) -19289*a(n-18) -3357*a(n-19) +6590*a(n-20) -1131*a(n-21) -848*a(n-22) +336*a(n-23) +12*a(n-24) -23*a(n-25) +3*a(n-26) for n>27

%e Some solutions for n=4

%e ..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..2....0..0..0..0

%e ..0..1..1..1....1..0..0..1....0..0..0..2....2..2..2..2....0..0..0..1

%e ..1..1..1..1....0..1..1..2....0..1..1..2....2..2..2..2....0..1..1..1

%e ..0..1..1..1....0..1..2..1....0..1..1..2....0..2..2..2....1..0..1..1

%e ..2..0..2..2....0..2..1..2....2..0..2..2....1..2..2..2....0..2..0..2

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 25 2014

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Last modified December 5 20:39 EST 2021. Contains 349558 sequences. (Running on oeis4.)