A229522 Final digit (in decimal system) of (n^n)^n, i.e., (n^n)^n mod 10.

1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6, 7, 6, 9, 0, 1, 6, 3, 6, 5, 6

Offset: 1

Author

José María Grau Ribas, Sep 25 2013

Keywords

• nonn
• base
• easy

Comments

Periodic sequence with period 10.

Links

• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,1).

Crossrefs

Cf. A002489, A120962, A364789 (initial digit).

Programs

Mathematica

Table[PowerMod[n^n, n, 10], {n, 200}]

PARI

a(n)=n%=10; lift(Mod(n,10)^n^n) \\ Charles R Greathouse IV, Dec 27 2013

Python

def A229522(n): return (0, 1, 6, 3, 6, 5, 6, 7, 6, 9)[n%10] # Chai Wah Wu, Aug 10 2023

Formula

a(n) = A120962(A002489(n)). - Michel Marcus, Aug 09 2023