2017-07-01から1日間の記事一覧
問題 Problem 44:Pentagon numbers Pentagonal numbers are generated by the formula, Pn=n(3n−1)/2. The first ten pentagonal numbers are:1, 5, 12, 22, 35, 51, 70, 92, 117, 145, ...It can be seen that P4 + P7 = 22 + 70 = 92 = P8. However, thei…