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!)
A238777 a(n) = floor((5^n+1)/(2*3^n)). 3
1, 1, 2, 3, 6, 10, 17, 29, 49, 82, 137, 229, 382, 638, 1063, 1772, 2953, 4923, 8205, 13675, 22792, 37987, 63312, 105521, 175868, 293114, 488524, 814207, 1357012, 2261686, 3769478, 6282463, 10470772, 17451288, 29085480 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) is the rounded-down perimeter of the Vicsek fractal after n iterations. The Vicsek fractal is a subset of the box fractal; for both types, the number of boxes = A000351(n). See illustrations in links.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Kival Ngaokrajang, Illustrations of initial terms

Eric Weisstein's World of Mathematics, Box Fractal

Wikipedia, Vicsek Fractal

FORMULA

a(n) = A034478(n)/3^n.

MAPLE

A238777:=n->floor((5^n+1)/(2*3^n)); seq(A238777(n), n=1..50); # Wesley Ivan Hurt, Mar 09 2014

MATHEMATICA

Table[Floor[(5^n + 1)/(2*3^n)], {n, 50}] (* Wesley Ivan Hurt, Mar 09 2014 *)

PROG

(Small Basic)

For n = 1 to 40

   x = (math.Power(5, n)+1)/(2*math.Power(3, n))

   a = math.Floor(x)

   TextWindow.Write(a+", ")

Endfor

(PARI)

vector(100, n, floor((5^n+1)/(2*3^n))) \\ Colin Barker, Mar 05 2014

(MAGMA) [Floor((5^n+1)/(2*3^n)): n in [1..40]]; // Vincenzo Librandi, Mar 11 2014

CROSSREFS

Cf. A000351, A034478.

Sequence in context: A023614 A001610 A324015 * A344615 A245437 A285665

Adjacent sequences:  A238774 A238775 A238776 * A238778 A238779 A238780

KEYWORD

nonn

AUTHOR

Kival Ngaokrajang, Mar 05 2014

STATUS

approved

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 July 1 16:27 EDT 2022. Contains 354973 sequences. (Running on oeis4.)