20904

Appears in sequences

• Numbers whose base-12 representation has exactly 5 runs.at n=11A043654
• a(n) = Sum_{d|4} phi(d)*n^(4/d).at n=12A054603
• 4 times 9-gonal numbers: a(n) = 2*n*(7*n-5).at n=39A152760
• Antidiagonal sums of the convolution array A213587.at n=11A213589
• Number of (n+2)X(7+2) 0..3 arrays with every consecutive three elements in every row and column not having exactly two distinct values, and in every diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=18A253024
• a(n) = r_4(n^2 + 1), where r_4(k) is the number of ways of writing k as a sum of 4 squares (A000118).at n=41A333173
• Numbers that are the sum of six fifth powers in two or more ways.at n=6A345507
• Numbers that are the sum of six fifth powers in exactly two ways.at n=6A346357
• a(n) = 5*Fibonacci(n) + (-1)^n.at n=19A371843