207751domain: NAppears in sequencesNumber of 2 X 2 matrices with all elements in {0,1,...,n} and determinant >= 3n.at n=27A210368Let p = prime(n). Smallest j such that q = j*2*p^3-1, r = j*p*2*q^2-1, s = j*p*2*r^2-1, and j*p*2*s^2-1 are prime numbers.at n=37A224612