141422domain: NAppears in sequencesa(n) is root of square starting with digit 2: first term of runs.at n=9A035069Triangular T(n,k) = T(n-1, k) + T(n-1, k-1) + 5*T(n-2, k-1), read by rows.at n=49A153518Triangular T(n,k) = T(n-1, k) + T(n-1, k-1) + 5*T(n-2, k-1), read by rows.at n=50A153518