42415

Appears in sequences

• a(n) = n*(2*n^2 + 5*n + 13)/2.at n=34A163655
• Number of 4X2 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 4 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=39A192703
• a(n) is the sum of (3^n mod 2^k) for k such that 2^k < 3^n.at n=9A337921