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 A064932 #43 Nov 18 2023 22:24:28
%S A064932 2,10,30,98,270,818,2382,7282,21818,65650,196406,589982,1768938,
%T A064932 5309294,15924930,47779238,143322850,429998586,1289970842,3869957114,
%U A064932 11609762666,34829416842,104488103446
%N A064932 Period of the continued fraction for sqrt(3^(2n+1)).
%C A064932 Limit_{n->oo} a(n)/3^n = 1.11... - _A.H.M. Smeets_, Oct 25 2017
%D A064932 R. K. Guy, personal communication.
%F A064932 a(n) = A003285(A013708(n)). - _Michel Marcus_, Sep 25 2019
%t A064932 Table[Length[Last[ContinuedFraction[Sqrt[3^(2n+1)] ]]], {n, 10}]
%Y A064932 Cf. A003285, A013708, A059927.
%K A064932 hard,nonn,more
%O A064932 1,1
%A A064932 _Wouter Meeussen_, Oct 26 2001
%E A064932 a(11)-a(13) from _A.H.M. Smeets_, Sep 28 2017
%E A064932 a(14) from _A.H.M. Smeets_, Oct 08 2017
%E A064932 a(15)-a(19) from _Daniel Suteu_, Jan 24 2019
%E A064932 a(20) from _Chai Wah Wu_, Sep 23 2019
%E A064932 a(21)-a(23) from _Chai Wah Wu_, Sep 25 2019