4194325domain: NAppears in sequencesa(n) = 2^n + n - 1.at n=22A052944Row sums of triangle A132735.at n=22A132736a(1)=1. a(n) = the smallest integer > a(n-1) such that |d(a(n)) - d(a(n-1))| = n-1, where d(m) = the number of positive divisors of m.at n=22A139695a(n) = 1 + sum{k=1 to n} A177268(k).at n=22A177269