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%I #7 Sep 08 2022 08:45:46
%S 2,5,10,25,50,125,250,625,1250,3125,6250,15625,31250,78125,156250,
%T 390625,781250,1953125,3906250,9765625,19531250,48828125,97656250,
%U 244140625,488281250,1220703125,2441406250,6103515625,12207031250
%N a(n) = 5*a(n-2) for n > 2; a(1) = 2, a(2) = 5.
%C Binomial transform is A162770, second binomial transform is A001077 without initial 1, third binomial transform is A162771, fourth binomial transform is A162772, fifth binomial transform is A162773.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,5).
%F a(n) = (3-(-1)^n)*5^(1/4*(2*n-1+(-1)^n))/2.
%F G.f.: x*(2+5*x)/(1-5*x^2).
%F a(n) = A026383(n) for n >= 1.
%o (Magma) [ n le 2 select 3*n-1 else 5*Self(n-2): n in [1..29] ];
%Y Cf. A000351 (powers of 5), A026383, A001077, A162770, A162771, A162772, A162773.
%K nonn,easy
%O 1,1
%A _Klaus Brockhaus_, Jul 19 2009