A303410 T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
0, 1, 0, 1, 3, 0, 2, 7, 10, 0, 3, 10, 28, 23, 0, 5, 27, 42, 119, 61, 0, 8, 45, 100, 168, 541, 162, 0, 13, 98, 290, 547, 902, 2327, 421, 0, 21, 193, 730, 2079, 4013, 3256, 10384, 1103, 0, 34, 379, 1700, 6322, 29411, 21361, 15852, 47491, 2890, 0, 55, 778, 4246, 17903
Offset: 1
Examples
Some solutions for n=5 k=4 ..0..1..0..0. .0..1..1..0. .0..1..0..1. .0..0..0..0. .0..0..0..0 ..1..0..1..1. .1..0..0..1. .1..0..1..0. .1..1..1..1. .1..0..1..0 ..0..0..0..0. .1..1..1..1. .0..1..0..1. .1..0..1..0. .0..1..0..1 ..0..1..0..0. .0..1..1..0. .0..0..0..0. .1..1..0..1. .1..1..1..1 ..1..0..1..1. .1..0..0..1. .1..1..1..1. .1..0..1..0. .0..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..180
Crossrefs
Formula
Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 2*a(n-1) +a(n-2) +2*a(n-3) -a(n-4)
k=3: [order 18]
k=4: [order 72]
Empirical for row n:
n=1: a(n) = a(n-1) +a(n-2)
n=2: a(n) = a(n-1) +3*a(n-2) -4*a(n-4) for n>5
n=3: [order 15] for n>17
n=4: [order 71] for n>72
Comments