180495domain: NAppears in sequencesG.f.: (x+4*x^3+x^5)/((1-x)^2*(1-x^2)^2*(1-x^3)^2).at n=39A083708Numbers k such that k and k+1 are both S-abundant numbers (A181487).at n=13A364861Numbers k such that each of k and k+1 is either a practical number (A005153) or an almost practical number (A174533).at n=33A387654