66094

Appears in sequences

• Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 3 which is symmetric after a rotation by 180 degrees.at n=6A123825
• Number of 1X5 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 1 zero-sum 5-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=30A192692
• Number of nX6 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=4A208686
• T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=49A208688
• Number of 5 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=5A208691
• a(n) = (1/(n+1)) * Sum_{k=0..n} k^4 * (k+1) * binomial(2*n-k,n-k).at n=7A390967