68653

Appears in sequences

• Becomes prime or 4 after exactly 10 iterations of f(x) = sum of prime factors of x.at n=7A048132
• Difference between largest number of complexity n in the sense of A005245 and smallest number of complexity n in the sense of A005245.at n=30A133374
• Triangle read by rows: row n contains sequence S_n = [s(1), ..., s(n)] where s(1) is the least semiprime pq such that the recurrence s(i+1) = sum of two prime factors of s(i) generates a chain of exactly n semiprimes.at n=45A171095
• a(n) is the first semiprime that starts a sequence of n distinct semiprimes under the map A001414.at n=9A345407