A193256 Number of spanning trees in the n-Sierpinski sieve graph.

3, 54, 524880, 803355125990400000, 4800637927396055428150118355522551808000000000000000000

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: A154604 A188798 A334248 * A319038 A340214 A088278

Adjacent sequences: A193253 A193254 A193255 * A193257 A193258 A193259

Keyword

nonn

Author

Alois P. Heinz, Jul 19 2011

Status

approved