999049domain: NPropertiesPrimalityPrimeyesAppears in sequencesprimes of the form 5n^2 + 4.at n=24A201483Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and one or three distinct values.at n=13A211815Number of 6Xn 0..1 arrays with rows unimodal and antidiagonals nondecreasing.at n=9A224413Prime numbersat n=78438