71522domain: NAppears in sequencesNumber of (n+1)X(n+1) -6..6 symmetric matrices with every 2X2 subblock having sum zero and two or three distinct values.at n=9A211256Numbers k such that 10k is a partition number.at n=4A225317Numbers k such that k^7*2^k - 1 is a prime.at n=19A367561