131320domain: NAppears in sequencesNumber of (n+3) X 8 0..2 matrices with each 4 X 4 subblock idempotent.at n=16A224725Least positive integer k such that both k and k*n belong to the set {m>0: m+1, m^2+1 and m^2+prime(m)^2 are all prime}.at n=45A261339