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