-733

Appears in sequences

• First order recursion: a(0)=1; a(n) = sigma(1,n) - a(n-1).at n=63A083238
• a(n) = A174817(n) - Mnr; where Mnr = A001228(26) = 808017424794512875886459904961710757005754368000000000, also called the Monster number, cf. A003131.at n=10A174818
• G.f. A(x) satisfies: 1/(1 - x) = A(x)*A(x^2)^2*A(x^3)^3*A(x^4)^4* ... *A(x^k)^k* ...at n=23A307648
• a(1) = -1, for n > 1, a(n) = Sum_{d|n, d<n} A340197(n/d) * a(d).at n=71A340140
• Expansion of Product_{k>=1} (1 - x^k)^prime(k+1).at n=18A353170