377670domain: NAppears in sequencesEngel series expansion (or "Egyptian product") for Khintchine's constant.at n=13A054544Numbers n such that 1 - Sum{k=1..n/2} A001223(2k-1)*(-1)^k = 0.at n=32A130643Numbers n such that 1 + S(n) = 0, where S(n) = (S(n-1) + A000040(n))*(-1)^n; S(0)=0, n=>1.at n=25A131196