685582domain: NAppears in sequencesEven semiprimes of the form prime(n)*prime(n+1) - 1.at n=12A103533Product of twin primes minus 1.at n=32A120875G.f.: exp( Sum_{n>=1} x^n/n * exp( Sum_{k>=1} sigma(n*k) * x^(n*k)/k ) ).at n=23A203320Semiprimes which are the product of a twin prime pair minus one.at n=11A269663