133400domain: NAppears in sequencesa(n) = (5*n^2 + 1)*n^2 / 6.at n=20A008354Number of evil primes (A027699) in range ]2^n,2^(n+1)].at n=21A095006a(n) = 4*(n + 1)*(n + 2)*(4*n + 3)/3.at n=28A267522Array read by antidiagonals: the number of directed elements with area n on the lattice T_{2k+1}.at n=48A296129