This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A246959 #36 Jun 14 2025 21:50:31
%S A246959 1,1,8,13824,71328803586048,
%T A246959 9798477119793909670551703700100284084649984
%N A246959 Numbers of (undirected) Hamiltonian cycles in the n-Sierpiński gasket graph.
%H A246959 R. M. Bradley, <a href="https://hal.archives-ouvertes.fr/jpa-00210189/">Statistical mechanics of the travelling salesman on the Sierpinski gasket</a>, J. Physique, 47 (1986), 9-14. doi:<a href="http://dx.doi.org/10.1051/jphys:019860047010900">10.1051/jphys:019860047010900</a>.
%H A246959 S.-C. Chang, L.-C. Chen. Hamiltonian walks on the Sierpinski gasket, J. Math. Phys. 52 (2011), 023301. doi:<a href="http://dx.doi.org/10.1063/1.3545358">10.1063/1.3545358</a>. arXiv:<a href="http://arxiv.org/abs/0909.5541">0909.5541</a>.
%H A246959 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HamiltonianCycle.html">Hamiltonian Cycle</a>.
%H A246959 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SierpinskiGasketGraph.html">Sierpiński Gasket Graph</a>.
%F A246959 For n >= 3, a(n) = 8 * 12^((3^(n-2)-3)/2).
%F A246959 For n >= 4, a(n) = (3*a(n-1))^3.
%t A246959 Join[{1, 1}, Table[8 12^((3^(n - 2) - 3)/2), {n, 3, 8}]] (* _Eric W. Weisstein_, Jun 17 2017 *)
%t A246959 Join[{1, 1}, RecurrenceTable[{a[3] == 8, a[n] == (3 a[n - 1])^3}, a, {n, 3, 8}]] (* _Eric W. Weisstein_, Mar 25 2018 *)
%o A246959 (Magma) [1,1] cat [Floor(8 * 12^((3^(n-2)-3)/2)): n in [3..10]]; // _Vincenzo Librandi_, Jun 15 2015
%Y A246959 Cf. A234635, A246957, A246958.
%K A246959 nonn
%O A246959 1,3
%A A246959 _Max Alekseyev_, Sep 08 2014