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%I #29 Oct 13 2022 14:25:29
%S 10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,
%T 4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,
%U 10,4,10,6,10,4,10,6,10,4,10,6,10,4,10,6,10,4
%N Period 4: repeat [10, 6, 10, 4].
%C Number of different remainders mod 10 of n-th powers (i.e., number of possible last decimal digits of n-th powers).
%C Continued fraction expansion of (124+sqrt(16926))/25. - _Klaus Brockhaus_, May 01 2010
%H Muniru A Asiru, <a href="/A167873/b167873.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1).
%F a(n) = 8 - 4*((n+1) mod 2) + 2*ceiling(n/4) - 2*floor(n/4). - _Wesley Ivan Hurt_, Mar 26 2014
%F a(n) = 15/2 - (5/2)*cos(n*Pi) - cos(n*Pi/2). - _Wesley Ivan Hurt_, Oct 05 2018
%e a(4) = 4 because the possible last decimal digits of 4th powers are 0, 1, 5, 6.
%p seq(op([10, 6, 10, 4]), n=0..30); # _Wesley Ivan Hurt_, Oct 06 2018
%t PadRight[{},80,{10,6,10,4}] (* _Harvey P. Dale_, Nov 29 2015 *)
%o (GAP) Flat(List([1..30],n->[10,6,10,4])); # _Muniru A Asiru_, Oct 06 2018
%Y Cf. A177015 (decimal expansion of (124+sqrt(16926))/25). - _Klaus Brockhaus_, May 01 2010
%K easy,nonn
%O 1,1
%A _Franz Vrabec_, Nov 14 2009
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