66858

Appears in sequences

• Number of 2X3 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 2 zero-sum 3-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=28A192698
• a(n) = binomial(n,2)*(2^(n-2) - n + 1).at n=12A342404