27104

Appears in sequences

• Convolution of partition numbers and Catalan numbers.at n=10A014329
• a(n) = A027144(2n, n-1).at n=6A027146
• Theta series of 20-dimensional lattice L_20 with group 2.M_22.2.at n=5A033288
• Triangle read by rows: T(n,k) is the number of noncrossing trees with n edges and k leaves at level 1.at n=58A101371
• Triangle, read by rows, where row n equals the inverse binomial transform of the crystal ball sequence for D_n lattice.at n=34A108556
• Number of 8-step left-handed knight's tours (moves only out two, left one) on an n X n board summed over all starting positions.at n=10A187178
• Sequence defined by a(1)=a(2)=1 and a(n) = gray(a(n-1) + a(n-2)), with gray(m) = A003188(m).at n=15A265385
• Smallest integer such that the sum of its n smallest divisors is a square.at n=32A289712
• Ordered perimeters p of primitive Pythagorean triangles no side of which is squarefree.at n=44A329392
• Numbers k such that k and k+1 are both phi-practical numbers (A260653).at n=31A330871
• Unitary Ruth-Aaron numbers: numbers k such that A008475(k) = A008475(k+1).at n=20A331000
• Number of subsets of {1..n} where some element is a difference of two consecutive elements.at n=15A364466