6718465domain: NAppears in sequencesPierpont 4-almost primes: numbers with exactly 4 prime divisors, not necessarily distinct, of the form 2^K*3^L + 1.at n=19A111344a(n) = 4*6^n+1.at n=8A199319a(n) = 4*n^4 + 1.at n=35A211412