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
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 19 2011
STATUS
approved