现行高中教材和同步练习册上,有这么一类由形如a_n=ba_(n-1)+c的递推式和初始值a_1确定的递推归纳型的数列问题。此类问题的通项公式探究起来,常有多种解法对培养学生发散思维,诱导创新解法大有裨益。样题:已知数列{a_n}的前n项和s_n=4a_n+3n+9 In the current high school textbooks and synchronous workbooks, there is a recurrence-inductive sequence problem that is determined by the recursion of the form a_n = ba_ (n-1) + c and the initial value a_1. The general formula for such questions explores, often a variety of solutions to develop students divergent thinking, to induce innovative solutions greatly beneficial. Sample Question: The first n terms of the known sequence {a_n} and s_n = 4a_n + 3n + 9 are known