125014domain: NAppears in sequencesNumber of (n+3) X 7 0..1 matrices with each 4 X 4 subblock idempotent.at n=21A224564a(n) is the sum of the terms of the symmetric square array defined by M(i,j) = prime(i)+i-j for i >= j and M(i,j) = M(j,i) if i < j.at n=34A308731