186966domain: NAppears in sequencesTriangular numbers for which the sum of the digits is a square.at n=28A117404Triangular numbers for which the sum of the digits equals the sum of the digits of the next triangular number.at n=30A117511Triangular arithmetic on half-squares: b(n)*(b(n) - 1)/2 where b(n) = floor(n^2/2).at n=35A227970