A250783 T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.
9, 21, 18, 46, 46, 36, 99, 106, 96, 72, 209, 238, 230, 196, 144, 436, 518, 534, 482, 396, 288, 901, 1106, 1194, 1152, 990, 796, 576, 1849, 2326, 2604, 2640, 2426, 2010, 1596, 1152, 3774, 4838, 5568, 5882, 5688, 5028, 4054, 3196, 2304, 7671, 9978, 11732, 12796
Offset: 1
Examples
Some solutions for n=4 k=4 ..0..0..1..0..0....0..0..0..1..0....0..0..0..0..0....1..0..1..1..0 ..0..0..1..0..0....0..0..0..1..1....0..0..0..0..0....1..0..1..1..0 ..0..0..1..0..0....0..0..0..1..1....0..0..0..0..1....1..0..1..1..1 ..0..0..1..0..1....0..0..0..1..1....1..1..1..1..0....1..0..1..1..1 ..0..0..1..0..1....0..0..0..1..1....1..1..1..1..0....1..0..1..1..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..544
Formula
Empirical for column k:
k=1: a(n) = 2*a(n-1); a(n) = 9*2^(n-1)
k=2: a(n) = 3*a(n-1) -2*a(n-2); a(n) = 25*2^(n-1) -4
k=3: a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3)
k=4: a(n) = 6*a(n-1) -14*a(n-2) +16*a(n-3) -9*a(n-4) +2*a(n-5)
k=5: a(n) = 8*a(n-1) -27*a(n-2) +50*a(n-3) -55*a(n-4) +36*a(n-5) -13*a(n-6) +2*a(n-7)
k=6: [order 9]
k=7: [order 11]
Empirical for row n:
n=1: a(n) = 3*a(n-1) -a(n-2) -2*a(n-3)
n=2: a(n) = 4*a(n-1) -4*a(n-2) -a(n-3) +2*a(n-4)
n=3: a(n) = 5*a(n-1) -8*a(n-2) +3*a(n-3) +3*a(n-4) -2*a(n-5)
n=4: a(n) = 5*a(n-1) -7*a(n-2) -2*a(n-3) +11*a(n-4) -5*a(n-5) -3*a(n-6) +2*a(n-7)
n=5: [order 8]
n=6: [order 9]
n=7: [order 10]
Comments