421111domain: NAppears in sequencesNumbers k such that k and k^2 use only the digits 1, 2, 3, 4 and 7.at n=20A136970Concatenation of multiplicities of prime divisors of highly composite numbers A002182(n).at n=37A245500Number of subsets of {1..n} where no two elements sum to a prime.at n=35A391562