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 A209466 Final digit of n^n - n. 0
 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 (list; graph; refs; listen; history; text; internal format)
 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 *) PROG (Perl) print ((\$_**\$_-\$_)%10) for (1..40); (PARI) a(n)=lift(Mod(n, 10)^n-n) \\ Charles R Greathouse IV, Mar 13 2012 CROSSREFS Cf. A056849. Sequence in context: A011168 A058672 A278215 * A277659 A258711 A127278 Adjacent sequences:  A209463 A209464 A209465 * A209467 A209468 A209469 KEYWORD nonn,easy,base AUTHOR Radu Borza, Mar 09 2012 STATUS approved

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Last modified February 20 02:07 EST 2018. Contains 299357 sequences. (Running on oeis4.)