4 lines
215 B
Text
4 lines
215 B
Text
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AddSumSquare[input_]:=Append[input,Total[IntegerDigits[Last[input]]^2]]
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NestUntilRepeat[a_,f_]:=NestWhile[f,{a},!MemberQ[Most[Last[{##}]],Last[Last[{##}]]]&,All]
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HappyQ[a_]:=Last[NestUntilRepeat[a,AddSumSquare]]==1
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