31719424

Appears in sequences

• Consider the Watanabe tag system defined in A291067; a(n) = number of binary words of length n which terminate at the empty word.at n=25A291780
• a(n) = the smallest number m such that gcd(tau(m), sigma(m)) = n where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).at n=18A324554