71211

Appears in sequences

• Triangle T(n, k) = Numbers of ways to place k points on a triangular grid of side n so that no two of them are adjacent. Triangle read by rows.at n=47A239567
• Number of ways to place 4 points on a triangular grid of side n so that no two of them are adjacent.at n=6A239570
• The number of irreducible balanced subsets of [n].at n=40A389802
• a(n) = A389802(2n+1).at n=20A389803