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!)
A017919 Powers of sqrt(5) rounded down. 10

%I #38 Sep 08 2022 08:44:43

%S 1,2,5,11,25,55,125,279,625,1397,3125,6987,15625,34938,78125,174692,

%T 390625,873464,1953125,4367320,9765625,21836601,48828125,109183006,

%U 244140625,545915033,1220703125,2729575167

%N Powers of sqrt(5) rounded down.

%C a(n) is the total length (rounded down to integer) of the elements of a variant of a 5-element fractal after n iterations, starting with 5 elements, each of whose length is 1/5 (in some units). See illustration in the Links. - _Kival Ngaokrajang_, Feb 26 2015

%H Vincenzo Librandi, <a href="/A017919/b017919.txt">Table of n, a(n) for n = 0..1000</a>

%H Kival Ngaokrajang, <a href="/A017919/a017919_3.pdf">Illustration of initial terms</a>

%t Floor[(Sqrt[5])^Range[0,40]] (* _Vincenzo Librandi_, Nov 20 2011 *)

%o (PARI) a(n)=sqrtint(5^n) \\ _Charles R Greathouse IV_, Nov 18 2011

%o (Magma) [Floor(Sqrt(5^n)): n in [0..40]]; // _Vincenzo Librandi_, Nov 20 2011

%Y Cf. A017920, A017921.

%K nonn

%O 0,2

%A _N. J. A. Sloane_

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 09:14 EDT 2024. Contains 371268 sequences. (Running on oeis4.)