260847domain: NAppears in sequencesn sets a record for the number of primes in {n, f(n), f(f(n)), ..., 1}, where f is the Collatz function defined by f(x) = x/2 if x is even; f(x) = 3x + 1 if x is odd.at n=19A078373Number of permutations in S_n that avoid the pattern 32541.at n=9A256204