求助：为什么不能显示图形？

matlab666

想动画显示散列图，却没有显示
Clear[tt]

9 E+ L, @$ Z; {2 t3 l) M2 F2 ytt = {1, 1/2^2, 1/3^2}
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{1,1/4,1/9}

3 _+ M% O! o! A8 c' B1 P+ n0 \6 [' J7 PDo[ListPlot[tt = Append[tt, 1/i^2]], {i, 4, 20}]
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matlab666

自己动手，丰衣足食--问题已解决
Clear[tt];
3 b% l0 ]' m0 s* g1 ttt = {1, 1/2^2, 1/3^2};
Do[tt = Append[tt, N[1/i^2]];
Print[ListPlot[tt, PlotRange -> {0, 1},
   PlotStyle -> PointSize[0.02]]], {i, 4, 20}]
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