login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A162963 a(n) = 5*a(n-2) for n > 2; a(1) = 2, a(2) = 5. 4

%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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)