login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A193256 Number of spanning trees in the n-Sierpinski sieve graph. 1
3, 54, 524880, 803355125990400000, 4800637927396055428150118355522551808000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(7) = 1280086429813445... has 498 decimal digits.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..7

E. Teufl and St. Wagner, Spanning trees of finite Sierpinski graphs, DMTCS proc. AG, 2006, 411-414

Eric Weisstein's World of Mathematics, Sierpinski Sieve Graph

Eric Weisstein's World of Mathematics, Spanning Tree

FORMULA

a(n) = (3/20)^(1/4) * (5/3)^(-(n-1)/2) * (540^(1/4))^(3^(n-1)).

MAPLE

a:= proc(n) local t;

      t:= (3/20)^(1/4) * (5/3)^(-(n-1)/2) * (540^(1/4))^(3^(n-1));

      Digits:= 10 +ceil(log[10](t));

      round(t)

    end:

seq(a(n), n=1..8);

MATHEMATICA

Table[2^(1/6 (-3 + 3^n)) 3^(1/4 (-1 + 3^n + 2 n)) 5^(1/12 (3 + 3^n - 6 n)), {n, 8}] (* Eric W. Weisstein, Jun 17 2017 *)

CROSSREFS

Sequence in context: A214006 A154604 A188798 * A319038 A227054 A088278

Adjacent sequences:  A193253 A193254 A193255 * A193257 A193258 A193259

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 19 2011

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 18 18:56 EDT 2019. Contains 328197 sequences. (Running on oeis4.)