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Decimal expansion of positive real number x such that Dedekind eta(sqrt(-1)*x) is maximized.
3

%I #16 Feb 16 2025 08:32:54

%S 5,2,3,5,2,1,7,0,0,0,1,7,9,9,9,2,6,6,8,0,0,5,3,4,4,0,4,8,0,6,1,0,9,7,

%T 4,1,0,1,7,2,1,3,9,8,4,8,8,5,3,1,5,7,2,7,1,7,7,7,9,6,5,7,6,6,2,6,8,4,

%U 0,9,1,5,2,1,1,9,6,6,3,8,5,5,9,1,8,0,5,2,5,6,4,1,0,2,5,9,7,2,4,9

%N Decimal expansion of positive real number x such that Dedekind eta(sqrt(-1)*x) is maximized.

%C A097079 gives the maximum itself. (A097078, A097079) are the coordinates of the maximum on the first graph on the linked World of Mathematics page.

%H Stanislav Sykora, <a href="/A097078/b097078.txt">Table of n, a(n) for n = 0..2000</a>

%H S. Sykora, <a href="https://oeis.org/wiki/File:OptimizationFunctions.txt">PARI/GP scripts for optimization tasks</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DedekindEtaFunction.html">Dedekind Eta Function</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Dedekind_eta_function">Dedekind eta function</a>

%e 0.523521700017999266800534404806109741017213984885315727177796576626840915211966...

%t FindMinimum[ 1 / DedekindEta[x*I], {x, .5235}, AccuracyGoal -> 100, MaxIterations -> 1000, WorkingPrecision -> 100] (* _Ed Pegg Jr_, Jul 29 2004 *)

%o (PARI) See the link

%Y Cf. A097079 (eta(A097078*i)).

%K cons,nonn,changed

%O 0,1

%A _Rick L. Shepherd_, Jul 24 2004

%E Edited by _Robert G. Wilson v_ and _Vladeta Jovovic_, Jul 28 2004