1778112

Appears in sequences

• Euler totient function (A000010) of 2^n - 1.at n=20A053287
• Triangle a(n,k) = binomial(n,k)*binomial(n+1,k+1)*binomial(n+2,k+2) read by rows.at n=39A187552
• a(n) = n^3*(n+1)^3*(n+2)^3/72.at n=6A202109
• a(n) = 21*a(n-2) + 7*a(n-3), with a(0)=a(1)=0, a(2)=9.at n=10A215484
• Smaller of pairs (m, n), such that the difference of their squares is a cube and the difference of their cubes is a square.at n=19A261296
• Integers that can be written m = k*tau(k) = q*tau(q) where (k, q) is a primitive solution of this equation and tau(k) is the number of divisors of k.at n=26A338384
• a(n) = phi(8^n-1), where phi is Euler's totient function (A000010).at n=6A366654