■ベキ和の周期性(その5)
ベキ和
Sk(n)=1^k+2^k+3^k+・・・+n^k
についても類似の結果が得られるに違いない。
a^k (mod3)の場合について調べてみると・・・
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a :0,1,2,3,4,5,6,7,8,9
a :0,1,2,0,1,2,0,1,2,0
a^2:0,1,1,0,1,1,0,1,1,0
a^3:0,1,2,0,1,2,0,1,2,0
a^4:0,1,1,0,1,1,0,1,1,0
a^5:0,1,2,0,1,2,0,1,2,0
a^6:0,1,1,0,1,1,0,1,1,0
a^7:0,1,2,0,1,2,0,1,2,0
a^8:0,1,1,0,1,1,0,1,1,0
a^9:0,1,2,0,1,2,0,1,2,0
S1(n)=1,0,0,1,0,0,・・・(00になるまで周期3)
S2(n)=1,2,2,0,1,1,2,2,0,0,・・・(00になるまで周期9=3^2)
S3(n)=1,0,0,1,0,0,・・・=S1(n)
S4(n)=1,2,2,0,1,1,2,2,0,0,・・・=S2(n)
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