%I A000689
%S A000689 1,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,
%T A000689 8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,
%U A000689 4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6,2,4,8,6
%N A000689 Final decimal digit of 2^n.
%H A000689 <a href="Sindx_Fi.html#final">Index entries for sequences related to 
               final digits of numbers</a>
%F A000689 Periodic with period 4.
%F A000689 a(n)=(1/6)*{8*(i mod 4)-[(i+1) mod 4]+2*[(i+2) mod 4]+11*[(i+3) mod 4]}-5*{1-[((i+1)!+1) 
               mod (i+1)]}, with n>=0. - Paolo P. Lava (ppl(AT)spl.at), Jun 25 2007
%p A000689 P:=proc(n) local a,i; for i from 0 by 1 to n do a:=1/6*(8*(i mod 4)-((i+1) 
               mod 4)+2*((i+2) mod 4)+11*((i+3) mod 4))-5*(1-(((i+1)!+1) mod (i+1))); 
               print(a); od; end: P(100); - Paolo P. Lava (ppl(AT)spl.at), Jun 25 
               2007
%o A000689 (Other) sage: [power_mod(2,n,10)for n in xrange(0, 81)] # [From Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Nov 03 2009]
%Y A000689 Sequence in context: A036117 A116624 A125733 this_sequence A132137 A011180 
               A103546
%Y A000689 Adjacent sequences: A000686 A000687 A000688 this_sequence A000690 A000691 
               A000692
%K A000689 nonn,new
%O A000689 0,2
%A A000689 N. J. A. Sloane (njas(AT)research.att.com).