1560281088domain: NAppears in sequencesExpansion of (1-3x+4x^2-3x^3+x^4)/(1-2x)^2.at n=28A084861Expansion of x^3*(3*x - 2)/(2*x - 1)^3.at n=26A268586a(1)= 2. For n > 1, a(n) is the least number k such that k, k - a(n-1) and k + a(n-1) all have n prime divisors counted by multiplicity.at n=25A365852