23780

Appears in sequences

• Sum of 10 positive 9th powers.at n=19A003399
• Number of n-step spirals on hexagonal lattice.at n=13A006776
• Number of nodes in regular n-gon with all diagonals drawn.at n=28A007569
• Number of intersection points of diagonals of an n-gon in general position, plus number of vertices.at n=29A014626
• Number of nonisomorphic and nonantiisomorphic reflexive transitive and cotransitive (complement is transitive) relations.at n=13A030270
• Number of partitions of n into parts not of the form 23k, 23k+6 or 23k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 10 are greater than 1.at n=39A035994
• a(n) = n*(2*n+5)*(n-1)/6.at n=41A051925
• Numbers k such that k | sigma_9(k) - phi(k)^9.at n=30A055703
• a(n) = n * Pell(n).at n=10A093967
• Practical numbers z such that z^2 = x^2 + y^2 for some practical numbers x and y with gcd(x,y,z) = 4.at n=35A294112