1591596domain: NAppears in sequencesNumbers such that the three numbers before and the three numbers after are squarefree semiprimes.at n=10A358657Terms k of A358657 such that lpf(k-1) and lpf(k+1) are twin primes pair, where lpf(k) = A020639(k) is the least prime dividing k.at n=1A378265