OFFSET
1,3
COMMENTS
Triangle T(n, k) is irregularly shaped: 1 <= k <= A239438(n). First row corresponds to n = 1.
The maximal number of points that can be placed on a triangular grid of side n so that no two of them are adjacent is given by A239438(n).
Without the restriction "non-equivalent (mod D_3)" numbers are given by A239567.
LINKS
Heinrich Ludwig, Table of n, a(n) for n = 1..136
EXAMPLE
Triangle begins
1;
1;
2, 2, 1;
3, 6, 6, 1;
4, 16, 32, 24, 7, 1;
5, 32, 113, 200, 176, 66, 6;
7, 60, 329, 1053, 1976, 2096, 1162, 302, 34, 2;
8, 100, 790, 3932, 12565, 25676, 32963, 25638, 11294, 2493, 222, 7;
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Heinrich Ludwig, Mar 22 2014
STATUS
approved