21167

Appears in sequences

• a(n) = 48*n^2 - 1.at n=21A065532
• Frobenius number of the numerical semigroup generated by consecutive hex numbers.at n=5A069759
• Largest integer not expressible as a nonnegative linear combination of n and n^2 + 1.at n=27A087908
• Numbers k such that 7*R_k - 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=12A099420
• Numerator of next-best approximation to harmonic numbers. a(n) = Numerator of (A055573(n)-1)th convergent of n-th harmonic number, Sum_{k=1..n} 1/k.at n=11A113123
• Binomial transform of [1, 4, 10, 20, 0, 0, 0, ...].at n=19A143131
• a(n) = 784*n - 1.at n=26A158399
• a(n) = 12*n^2 - 1.at n=42A158463
• Semiprimes which are the sum of three distinct positive cubes in two or more distinct ways.at n=33A180089
• Sum of the squarefree parts of the partitions of n into 6 parts.at n=34A309481
• Number of solutions to 1^3*k_1 + 2^3*k_2 + ... + n^3*k_n = 1, where k_i are from {-1,0,1}, i=1..n.at n=18A369735