找规律,求第N项:3,13,21,23,33,41,43,53,63,63.3,13,21,23,33,41,43,53,63,63,73,83,91,93.103,111,113,123,133,133,143,153,161,163,173,181,183,193,203,203,213.我觉得应该分成两段来求.可就是找不出..

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找规律,求第N项:3,13,21,23,33,41,43,53,63,63.3,13,21,23,33,41,43,53,63,63,73,83,91,93.103,111,113,123,133,1

找规律,求第N项:3,13,21,23,33,41,43,53,63,63.3,13,21,23,33,41,43,53,63,63,73,83,91,93.103,111,113,123,133,133,143,153,161,163,173,181,183,193,203,203,213.我觉得应该分成两段来求.可就是找不出..
找规律,求第N项:3,13,21,23,33,41,43,53,63,63.
3,13,21,23,33,41,43,53,63,63,73,83,91,93.103,111,113,123,133,133,143,153,161,163,173,181,183,193,203,203,213.
我觉得应该分成两段来求.可就是找不出..

找规律,求第N项:3,13,21,23,33,41,43,53,63,63.3,13,21,23,33,41,43,53,63,63,73,83,91,93.103,111,113,123,133,133,143,153,161,163,173,181,183,193,203,203,213.我觉得应该分成两段来求.可就是找不出..
第3项是21,6项是41,13项是91,16项是111,23项是161,26项是181可以推出当n的尾数是3的时候,第n项是7n;当n的尾数是6的时候,第n项是7n-1.
尾数是2的是7n-8,尾数是1的是7n-4,尾数是4的是7n-5,尾数是5的是7n-2,尾数是7的是7n-6,尾数是8的是7n-3,尾数是9的是7n,尾数是0的是7n-7
(上面第二行和第三行的n要大于等于2.第一次遇到这种题,希望不会出现错误)