119241

Appears in sequences

• Number of 3 X 3 integer matrices with elements in the range [ -n,n ] which represent a rotation of order 2.at n=26A053171
• a(n) is the number of ways to select an ordered pair of subsets of {2,...,n} such that each pair of elements from different subsets are relatively prime.at n=14A260185
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where A(n,k) = Sum_{i=0..k*n} 3^i * Sum_{j=0..i} (-1)^j * binomial(i,j) * binomial(i-j,n)^k.at n=17A384364