104926domain: NAppears in sequencesNumber of n-digit 7-smooth numbers (A002473).at n=37A085630a(n) = a(n-2) + 4*a(n-4) - 2*a(n-8) - a(n-10), with a[0..9] = [1, 1, 1, 2, 3, 5, 7, 13, 18, 31].at n=27A365274