21235

Appears in sequences

• Congruence classes of triangles which can be drawn using lattice points in n X n grid as vertices.at n=18A028419
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 39 ones.at n=1A031807
• G.f. satisfies: A(x) = A(x^2 + x^3)/(1-x).at n=21A251572
• a(n) = 4*p(n-1)*p(n+1) - p(n)^2, where p(k) = k-th prime.at n=21A327447
• Numbers that are the sum of five fourth powers in three or more ways.at n=31A344243
• Numbers that are the sum of five fourth powers in four or more ways.at n=1A344354
• Numbers that are the sum of five fourth powers in exactly four ways.at n=1A344355
• Table read by antidiagonals: Place k equally spaced points on each side of a regular n-gon and join every pair of these n*k points by a chord; T(n,k) (n >= 3, k >= 0) gives the number of internal vertices in the resulting planar graph.at n=39A367303
• a(n) is the smallest integer k > 2*n such that Product_{i=1..n} (k - i) has no prime factor p in n < p < 2*n.at n=29A386620