18476

Appears in sequences

• One-sixtieth of the even leg of Pythagorean triangles whose other sides are both primes (other than 3, 5 or 13).at n=42A068485
• Triangle read by rows: T(n,k) is the coefficient of t^k (k>=0) in the polynomial P[n,t] defined by P[1,t] = P[2,t] = 1, P[3,t] = 1+t, P[n,t] = P[n-1,t] + P^2[n-2,1] for n >= 4.at n=35A103525
• Self-avoiding walks with n steps on the truncated trihexagonal tiling or (4,6,12) lattice.at n=15A249795
• Triangle read by rows: T(n,m) (n >= m >= 1) = number of chambers (or regions) formed by drawing the line segments connecting any two of the (n+1) X (m+1) lattice points in an n X m lattice polygon.at n=38A288187
• Expansion of Product_{k>=1} 1/(1 + x^k)^(sigma_2(k)).at n=16A288422
• Number T(n,k) of involutions of [n] having exactly k peaks; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.at n=34A303648
• a(n) is a number of lattice points in 3D Cartesian grid between cube with edge length 2*n centered in origin and its inscribed sphere. Three pairs of the cube's faces are parallel to the planes XOY, XOZ, YOZ respectively.at n=17A303743
• Number of length-n quasiperiodic binary strings.at n=26A320434
• Irregular table read by rows: T(n,k) is the number of k-gons, k>=3, formed inside a right triangle by the straight line segments mutually connecting all vertices and points on the two shorter edges whose positions equal the Farey series of order n.at n=35A359971