276085domain: NAppears in sequencesNumber of 3 X n binary matrices with no zero rows or columns, up to row and column permutation.at n=28A055609Semiprimes A001358(k) = p*q such that p*q+p+q and r*s+r+s are consecutive primes, where A001358(k+1)=r*s.at n=36A330478