cp's OEIS Frontend

A147818 Period 4: repeat [5, 9, 9, 5].

%I A147818 #24 Mar 15 2024 02:20:13
%S A147818 5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,
%T A147818 9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,
%U A147818 5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5,9,9,5,5
%N A147818 Period 4: repeat [5, 9, 9, 5].
%C A147818 Last digit of the number whose binary representation is the concatenation of n 1's, 2n-1 0's and n 1's.
%C A147818 a(n) is the final digit of A147539(n).
%H A147818 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,-1,1).
%F A147818 a(n+1) = 7-2*cos(Pi*n/2)+2*sin(Pi*n/2). - _R. J. Mathar_, Oct 08 2011
%F A147818 a(n) = a(n-1)-a(n-2)+a(n-3) for n>3. G.f.: x*(5*x^2+4*x+5)/((1-x)*(x^2+1)). [_Colin Barker_, Nov 04 2012]
%F A147818 a(n) = a(n-4) for n>4. - _Wesley Ivan Hurt_, Jul 09 2016
%p A147818 A010879 := proc(n) n mod 10; end:
%p A147818 A147539 := proc(n) 2^n-1+2^(4*n-1)-2^(3*n-1); end:
%p A147818 A147818 := proc(n) A010879(A147539(n)); end: # _R. J. Mathar_, Jan 22 2009
%p A147818 seq(op([5, 9, 9, 5]), n=1..40); # _Wesley Ivan Hurt_, Jul 09 2016
%t A147818 PadRight[{}, 100, {5, 9, 9, 5}] (* _Wesley Ivan Hurt_, Jul 09 2016 *)
%o A147818 (Magma) &cat [[5, 9, 9, 5]^^30]; // _Wesley Ivan Hurt_, Jul 09 2016
%Y A147818 Cf. A138120, A147539.
%K A147818 base,easy,nonn
%O A147818 1,1
%A A147818 _Omar E. Pol_, Nov 14 2008, Jan 25 2009
%E A147818 More terms from _R. J. Mathar_, Jan 22 2009