6890624domain: NAppears in sequencesNumbers k such that k and k+1 are both refactorable numbers.at n=24A114617Numbers k such that k and k+1 are both divisible by the number of their divisors over the Eisenstein integers.at n=8A351854Numbers k such that k and k + 1 each have 10 prime divisors, counted with multiplicity.at n=5A369897