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 A308155 Number of (undirected) cycles in the n-Hanoi graph. 1
 1, 11, 1761, 6560212131, 282779810128722710004851715561, 22612323802416302740572466532825193607455652273991093701620185148186749274755003474250171 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(7) has 266 decimal digits and a(8) has 796 decimal digits. - Andrew Howroyd, Sep 10 2019 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..8 Eric Weisstein's World of Mathematics, Graph Cycle Eric Weisstein's World of Mathematics, Hanoi Graph FORMULA a(n) = Sum_{k=1..n} 3^(n-k)*A125295(k-1)^3. - Andrew Howroyd, Sep 10 2019 PROG (PARI) a(n)={my(s=1, d=1); for(i=2, n, d=d^2+d^3; s = 3*s + d^3); s} \\ Andrew Howroyd, Sep 10 2019 CROSSREFS Cf. A125295, A288796, A308134. Sequence in context: A222841 A287035 A297004 * A222874 A028453 A024151 Adjacent sequences:  A308152 A308153 A308154 * A308156 A308157 A308158 KEYWORD nonn AUTHOR Eric W. Weisstein, May 14 2019 EXTENSIONS a(4)-a(6) from Andrew Howroyd, Sep 10 2019 STATUS approved

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Last modified July 25 23:39 EDT 2021. Contains 346294 sequences. (Running on oeis4.)