Because the second differences are the same, a second degree polynomial solution is indicated. The solution was found using the Trendline feature in Excel, found under the Insert Menu. The regression could also be done using the statistics features of graphing calculators. This type of strategy to finding a pattern in numbers is possible at the secondary level because of technology. The solution of y=.5x²+.5x+4E-12 is equivalent to the solution of f(n) = a_n=n(n+1)/2.