A239405 T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it, modulo 4.
2, 4, 5, 8, 23, 12, 16, 105, 129, 28, 32, 478, 1337, 698, 66, 64, 2165, 13977, 16449, 3805, 156, 128, 9811, 144762, 394509, 205969, 20818, 368, 256, 44399, 1504399, 9340070, 11334364, 2590704, 113774, 868, 512, 201006, 15591122, 222457036, 614216271
Offset: 1
Examples
Some solutions for n=3 k=4 ..0..0..3..3....3..1..0..0....0..3..3..1....0..0..3..3....3..3..1..3 ..0..0..0..2....0..0..3..3....3..3..0..2....3..3..0..2....0..3..2..0 ..0..0..0..2....3..1..3..2....2..2..3..2....0..0..3..1....0..2..2..3
Links
- R. H. Hardin, Table of n, a(n) for n = 1..180
Formula
Empirical for column k:
k=1: a(n) = 2*a(n-1) +2*a(n-3)
k=2: [order 16]
k=3: [order 64]
Empirical for row n:
n=1: a(n) = 2*a(n-1)
n=2: a(n) = 3*a(n-1) +12*a(n-2) -18*a(n-3) -29*a(n-4) +19*a(n-5) +38*a(n-6) +8*a(n-7)
n=3: [order 25]
n=4: [order 91]
Comments