观察下列三行数①1,4,9,16,25,②2,5,10,17,26,[3]1,7,17,31,49.规律是甚么
问题描述:
观察下列三行数①1,4,9,16,25,②2,5,10,17,26,[3]1,7,17,31,49.规律是甚么
答
①第n个数刚好是n²
②第n个数刚好是n²+1
③第n个数刚好是2n²-1