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 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

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