|
%I #17 Jun 13 2015 00:55:17
%S 1,5,6,25,31,125,156,625,781,3125,3906,15625,19531,78125,97656,390625,
%T 488281,1953125,2441406,9765625,12207031,48828125,61035156,244140625,
%U 305175781,1220703125,1525878906,6103515625,7629394531,30517578125,38146972656,152587890625
%N Expansion of x*(1+5*x-5*x^3)/(1-6*x^2+5*x^4).
%H Colin Barker, <a href="/A249222/b249222.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 (0,6,0,-5).
%F a(n) = 6*a(n-2)-5*a(n-4).
%t CoefficientList[Series[(1 + 5 x - 5 x^3)/(1 - 6 x^2 + 5 x^4), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 23 2014 *)
%o (PARI) Vec((1+5*x-5*x^3)/(1-6*x^2+5*x^4) + O(x^100))
%o (PARI) a(n)=round((9-(-1)^n)*5^(n\2)/8) \\ _Tani Akinari_, Oct 26 2014
%Y Cf. A022163, A022165, A249221.
%K nonn,easy
%O 1,2
%A _Colin Barker_, Oct 23 2014
|
