2125765domain: NAppears in sequencesPositions where A007600 increases.at n=40A007601Pierpont 4-almost primes: numbers with exactly 4 prime divisors, not necessarily distinct, of the form 2^K*3^L + 1.at n=14A111344a(n) = 4*3^n + 1.at n=12A199108a(n) = 4*9^n+1.at n=6A199562a(n) = 4*n^4 + 1.at n=26A211412