OFFSET
1,5
COMMENTS
Equivalently, the minimum number of X-pentominoes needed to cover an m X n grid.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..276
Eric Weisstein's World of Mathematics, Domination Number
Eric Weisstein's World of Mathematics, Grid Graph
FORMULA
T(m,n) = T(n,m).
T(1,n) = ceiling(n/3); T(2,n) = floor(n/2) + 1.
EXAMPLE
Table begins:
===================================
m\n | 1 2 3 4 5 6 7 8 9
----+------------------------------
1 | 1 1 1 2 2 2 3 3 3 ...
2 | 1 2 2 3 3 4 4 5 5 ...
3 | 1 2 3 4 4 5 6 7 7 ...
4 | 2 3 4 4 6 7 7 8 10 ...
5 | 2 3 4 6 7 8 9 11 12 ...
6 | 2 4 5 7 8 10 11 12 14 ...
7 | 3 4 6 7 9 11 12 14 16 ...
8 | 3 5 7 8 11 12 14 16 18 ...
9 | 3 5 7 10 12 14 16 18 20 ...
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Andrew Howroyd, Jan 17 2022
STATUS
approved