21014

Appears in sequences

• Numbers that are the sum of 5 positive 7th powers.at n=32A003372
• Triangle read by rows: T(n,k) is the number of hill-free Schroeder paths of length 2n that have k weak ascents (1<=k<=n-1 for n>=2; k=1 for n=1). A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1. A weak ascent in a Schroeder path is a maximal sequence of consecutive U and H steps.at n=38A114691
• (prime(n))^3-(nonprime(n))^3 .at n=9A163121
• Sums of two successive primes s such that s+-3 are primes.at n=36A179485
• Numbers that are both a sum and a difference of two positive cubes.at n=38A225908
• Number of partitions of n such that (maximal multiplicity of parts) = (multiplicity of the least part).at n=39A240303
• Total number of congruence subgroups of PSL(2,Z) of genus n.at n=9A258691
• Positive numbers that are the sum of two (possibly negative) cubes in at least 2 ways (primitive solutions).at n=34A293647
• Sum of two (possibly negative) coprime cubes in at least 2 ways, but not the sum of 2 noncoprime cubes.at n=18A293648