107027domain: NAppears in sequencesCollatz trajectory starting at 3711.at n=21A179623Least number x such that x^n has n digits equal to k. Case k = 2.at n=30A285449a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} binomial(k+2,3) * a(k) * a(n-1-k).at n=6A386453