OFFSET
0,3
COMMENTS
Note: cyclic with a period of 20 for n > 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).
FORMULA
a(n) = (n^n-n) mod 10
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 *)
PROG
(Perl) print (($_**$_-$_)%10) for (1..40);
(PARI) a(n)=lift(Mod(n, 10)^n-n) \\ Charles R Greathouse IV, Mar 13 2012
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Radu Borza, Mar 09 2012
STATUS
approved