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A163141 a(n) = 5*a(n-2) for n > 2; a(1) = 4, a(2) = 5.

%I A163141 #9 Sep 08 2022 08:45:46
%S A163141 4,5,20,25,100,125,500,625,2500,3125,12500,15625,62500,78125,312500,
%T A163141 390625,1562500,1953125,7812500,9765625,39062500,48828125,195312500,
%U A163141 244140625,976562500,1220703125,4882812500,6103515625,24414062500
%N A163141 a(n) = 5*a(n-2) for n > 2; a(1) = 4, a(2) = 5.
%C A163141 Apparently the same as A133632 without initial 1.
%C A163141 Binomial transform is A163069, second binomial transform is A163070, third binomial transform is A163071, fourth binomial transform is A108404 without initial 1, fifth binomial transform is A163072.
%H A163141 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,5).
%F A163141 a(n) = (5-3*(-1)^n)*5^(1/4*(2*n-1+(-1)^n))/2.
%F A163141 G.f.: x*(4+5*x)/(1-5*x^2).
%t A163141 LinearRecurrence[{0,5},{4,5},30] (* _Harvey P. Dale_, Dec 20 2021 *)
%o A163141 (Magma) [ n le 2 select n+3 else 5*Self(n-2): n in [1..29] ];
%o A163141 (PARI) Vec(x*(4+5*x)/(1-5*x^2) + O(x^30)) \\ _Jinyuan Wang_, Mar 23 2020
%Y A163141 Cf. A133632, A108404, A163069, A163070, A163071, A163072.
%K A163141 nonn
%O A163141 1,1
%A A163141 _Klaus Brockhaus_, Jul 21 2009