A204817 Final nonzero digit of n^n in base 7.

1, 1, 4, 6, 4, 3, 1, 1, 1, 1, 4, 2, 1, 6, 4, 1, 2, 5, 1, 5, 1, 6, 1, 4, 1, 4, 4, 6, 4, 1, 1, 3, 2, 6, 1, 3, 1, 2, 2, 1, 2, 6, 1, 1, 4, 6, 4, 3, 1, 1, 1, 1, 4, 2, 1, 6, 1, 1, 2, 5, 1, 5, 1, 1, 1, 4, 1, 4, 4, 6, 4, 1, 1, 3, 2, 6, 1, 2, 1, 2, 2, 1, 2, 6, 1

Offset: 0

Author

José María Grau Ribas, Jan 19 2012

Keywords

• nonn
• easy
• base

Programs

Mathematica

f[0]=1;f[n_]:=Module[{m=n^n},While[Mod[m,7]==0,m=m/7];Mod[m,7]];Table[f[i],{i,0,100}]

PARI

a(n)=lift(Mod(n/7^valuation(n,7),7)^n) \\ Charles R Greathouse IV, Jan 23 2012