13198911domain: NAppears in sequencesDenominators of continued fraction convergents to sqrt(419).at n=17A041797Number of (n+2)X(3+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=9A252329