A233174 T(n,k)=Number of nXk 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally, diagonally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).
1, 1, 3, 3, 8, 11, 10, 80, 80, 48, 36, 800, 2688, 896, 236, 136, 8576, 78336, 96256, 10496, 1248, 528, 92672, 2469888, 7938048, 3497984, 124928, 6896, 2080, 1009664, 76447744, 736362496, 808583168, 127533056, 1495040, 39168, 8256, 11018240
Offset: 1
Examples
Some solutions for n=3 k=4 ..0..1..0..2....0..1..2..5....0..1..2..4....0..1..5..2....0..1..2..1 ..2..4..0..1....0..1..2..0....0..4..3..1....5..3..0..3....0..1..5..1 ..5..1..5..4....5..1..3..5....3..4..5..4....5..4..5..3....0..4..2..4
Links
- R. H. Hardin, Table of n, a(n) for n = 1..287
Formula
Empirical for column k:
k=1: a(n) = 12*a(n-1) -44*a(n-2) +48*a(n-3)
k=2: a(n) = 16*a(n-1) -48*a(n-2)
k=3: a(n) = 48*a(n-1) -448*a(n-2) +1024*a(n-3)
k=4: a(n) = 128*a(n-1) -2816*a(n-2) +16384*a(n-3)
k=5: [order 7]
k=6: [order 10]
k=7: [order 20]
Empirical for row n:
n=1: a(n) = 6*a(n-1) -8*a(n-2) for n>3
n=2: a(n) = 12*a(n-1) -128*a(n-3) for n>4
n=3: a(n) = 32*a(n-1) +64*a(n-2) -3072*a(n-3) +8192*a(n-4) for n>5
n=4: [order 7] for n>8
n=5: [order 10] for n>11
n=6: [order 24] for n>25
n=7: [order 47] for n>48
Comments