A209466 Final digit of n^n - n.
1, 0, 2, 4, 2, 0, 0, 6, 8, 0, 0, 0, 4, 0, 2, 0, 0, 0, 6, 0, 0, 0, 2, 4, 2, 0, 0, 6, 8, 0, 0, 0, 4, 0, 2, 0, 0, 0, 6, 0, 0, 0, 2, 4, 2, 0, 0, 6, 8, 0, 0, 0, 4, 0, 2, 0, 0, 0, 6, 0, 0, 0, 2, 4, 2, 0, 0, 6, 8, 0, 0, 0, 4, 0, 2, 0, 0, 0, 6, 0, 0, 0, 2, 4, 2, 0, 0
Offset: 0
References
- R. Euler & J. Sadek, "A number that gives the units of n^n", Journal of Recreational Mathematics 29:3 (1998), pp. 203-204.
Links
- Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1).
Crossrefs
Cf. A056849.
Programs
-
Maple
[seq((n^n-n) mod 10, n=1..40)];
-
Mathematica
Join[{1}, Table[Mod[PowerMod[n, n, 10] - n, 10], {n, 100}]] (* T. D. Noe, Mar 13 2012 *) PadRight[{1},120,{0,0,2,4,2,0,0,6,8,0,0,0,4,0,2,0,0,0,6,0}] (* Harvey P. Dale, May 21 2020 *) -
PARI
a(n)=lift(Mod(n,10)^n-n) \\ Charles R Greathouse IV, Mar 13 2012
-
Perl
print (($**$-$_)%10) for (1..40);
Formula
a(n) = (n^n-n) mod 10
Comments