%I #31 Sep 29 2019 19:02:45
%S 4,10,16,44,74,46,204,714,702,908,404,7754,1136,9886,8154,23578,65096,
%T 404762,23992,3514774,110124,4802160,6490450,180832,115972,770304,
%U 62665998,133093360,1019300318,60079334,113987888,5702124038,4463754028,713372392,38574516706,9096543466,7030527700,582442851838,16708770664,32628786870
%N Length of period of continued fraction expansion of square root of (2^(2n+1)+1).
%C Old definition was: "Quotient cycle length in continued fraction expansion of sqrt(2^(2n+1)+1)."
%F a(n) = A003285(A087289(n)). - _Michel Marcus_, Sep 26 2019
%t a[n_] := ContinuedFraction[Sqrt[2^(2n+1)+1]] // Last // Length; Table[a[n], {n, 2, 28}] (* _Jean-François Alcover_, Dec 11 2016 *)
%Y Cf. A003285, A059866, A059926, A087289.
%K nonn,nice,more
%O 2,1
%A _Labos Elemer_, Mar 01 2001
%E One more term from _David W. Wilson_, Jun 18 2001
%E Corrected and extended by _Naohiro Nomoto_, Nov 09 2001
%E a(29)-a(31) from _Daniel Suteu_, Jan 25 2019
%E a(32) from _Chai Wah Wu_, Sep 23 2019
%E a(33)-a(38) from _Chai Wah Wu_, Sep 25 2019
%E Simpler definition from _Bernard Schott_, Sep 26 2019
%E a(39)-a(41) from _Chai Wah Wu_, Sep 29 2019
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