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A250755 T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.

%I A250755 #6 Jul 23 2025 12:45:22
%S A250755 32,72,105,129,237,332,203,423,756,1029,294,663,1353,2361,3152,402,
%T A250755 957,2123,4239,7272,9585,527,1305,3066,6663,13089,22197,29012,669,
%U A250755 1707,4182,9633,20603,40023,67356,87549,828,2163,5471,13149,29814,63063,121593
%N A250755 T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.
%C A250755 Table starts
%C A250755 .....32......72.....129.....203.....294......402......527......669......828
%C A250755 ....105.....237.....423.....663.....957.....1305.....1707.....2163.....2673
%C A250755 ....332.....756....1353....2123....3066.....4182.....5471.....6933.....8568
%C A250755 ...1029....2361....4239....6663....9633....13149....17211....21819....26973
%C A250755 ...3152....7272...13089...20603...29814....40722....53327....67629....83628
%C A250755 ...9585...22197...40023...63063...91317...124785...163467...207363...256473
%C A250755 ..29012...67356..121593..191723..277746...379662...497471...631173...780768
%C A250755 ..87549..203601..367839..580263..840873..1149669..1506651..1911819..2365173
%C A250755 .263672..613872.1109649.1751003.2537934..3470442..4548527..5772189..7141428
%C A250755 .793065.1847757.3341223.5273463.7644477.10454265.13702827.17390163.21516273
%H A250755 R. H. Hardin, <a href="/A250755/b250755.txt">Table of n, a(n) for n = 1..241</a>
%F A250755 Empirical: T(n,k) = (3*(k+1)*(5*k+4)*3^n - (8*k^2+8*k)*2^n + (5*k^2-7*k))/4
%F A250755 Empirical for column k:
%F A250755 k=1: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (27*3^n-8*2^n-1)/2
%F A250755 k=2: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (63*3^n-24*2^n+3)/2
%F A250755 k=3: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (114*3^n-48*2^n+12)/2
%F A250755 k=4: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (180*3^n-80*2^n+26)/2
%F A250755 k=5: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (261*3^n-120*2^n+45)/2
%F A250755 k=6: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (357*3^n-168*2^n+69)/2
%F A250755 k=7: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3); a(n) = (468*3^n-224*2^n+98)/2
%F A250755 Empirical for row n:
%F A250755 n=1: a(n) = (17/2)*n^2 + (29/2)*n + 9
%F A250755 n=2: a(n) = 27*n^2 + 51*n + 27
%F A250755 n=3: a(n) = (173/2)*n^2 + (329/2)*n + 81
%F A250755 n=4: a(n) = 273*n^2 + 513*n + 243
%F A250755 n=5: a(n) = (1697/2)*n^2 + (3149/2)*n + 729
%F A250755 n=6: a(n) = 2607*n^2 + 4791*n + 2187
%F A250755 n=7: a(n) = (15893/2)*n^2 + (29009/2)*n + 6561
%e A250755 Some solutions for n=4 k=4
%e A250755 ..1..1..1..1..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
%e A250755 ..1..1..1..1..2....2..2..2..2..2....1..1..1..1..1....0..0..0..0..0
%e A250755 ..1..1..1..1..2....0..0..0..0..0....0..0..0..0..0....1..1..1..1..1
%e A250755 ..0..1..1..1..2....1..1..1..2..2....2..2..2..2..2....0..0..2..2..2
%e A250755 ..0..1..1..1..2....0..0..0..1..2....0..1..1..1..2....0..0..2..2..2
%Y A250755 Column 1 is A053152(n+3)
%K A250755 nonn,tabl
%O A250755 1,1
%A A250755 _R. H. Hardin_, Nov 27 2014