A233129 T(n,k) = number of n X k 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabeled 6-colorings with no clashing color pairs).
1, 1, 1, 3, 8, 3, 10, 80, 80, 10, 36, 896, 2688, 896, 36, 136, 10496, 96256, 96256, 10496, 136, 528, 124928, 3497984, 10674176, 3497984, 124928, 528, 2080, 1495040, 127533056, 1189609472, 1189609472, 127533056, 1495040, 2080, 8256, 17924096
Offset: 1
Examples
Some solutions for n=3 k=4 ..0..1..0..1....0..1..5..2....0..1..2..4....0..1..5..4....0..1..0..4 ..4..5..1..2....2..0..2..1....1..2..4..5....2..5..2..5....2..5..3..0 ..5..4..0..4....4..3..5..3....2..1..2..4....0..3..0..4....0..3..0..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..364
Crossrefs
Column 1 is A007582(n-2).
Formula
Empirical for column k:
k=1: a(n) = 6*a(n-1) -8*a(n-2) for 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) = 160*a(n-1) -6144*a(n-2) +86016*a(n-3) -393216*a(n-4)
k=5: [order 6]
k=6: [order 8]
k=7: [order 14]
Empirical for row n:
n=1: a(n) = 6*a(n-1) -8*a(n-2) for n>3
n=2: a(n) = 16*a(n-1) -48*a(n-2)
n=3: a(n) = 48*a(n-1) -448*a(n-2) +1024*a(n-3)
n=4: a(n) = 160*a(n-1) -6144*a(n-2) +86016*a(n-3) -393216*a(n-4)
n=5: [order 6]
n=6: [order 8]
n=7: [order 14]
Comments