第一个空20第二个空培渣6n第三个空6n+2当n为奇数时:(n+1)×1+(n+1)×2=3n+3当n为偶数时:(枣裤n+2)×1+n×2=配岩悄3n+2
当乎游孙n为奇数磨碧时:(n+1)×1+(n+1)×2=3n+3 当n为偶数时:(n+2)×1+n×2=3n+2 所岁链以依次填写6,8,12,14,18,20,...,6n,6n+2