先求m A[7,5]=A[5,1]+[(5-1)*m + (7-5)] = 1234 + 4m +2 = 1260 4m=24 m=6 A[6,4]=A[5,1] + [(4-1)*m+ (6-5)] = 1234+19=1253 參考 : https://zenreal.github.io/posts/8581/