57101domain: NAppears in sequencesT(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A027157.at n=13A027165Sum of squares of first n quarter-squares (A002620).at n=21A059859n*10^3-1, n*10^3-3, n*10^3-7 and n*10^3-9 are all prime.at n=29A064977