A244257 - OEIS

%I #5 Jun 24 2014 04:21:25

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

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

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

%N Decimal expansion of the asymptotic evaluation of the constrained maximum of a certain quadratic form.

%C The quadratic form to maximize is (sum_(k>=1) x(k)/k)^2 + sum_(k>=1) (x(k)/k)^2, subject to the constraint (sum_(k>=1) x(k)^2) <= 1.

%D Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 3.12 Du Bois Reymond's constants, p. 239.

%F (Pi/xi)^2, where xi is the smallest positive solution of the equation x+tan(x)=0.

%e 2.397945586114436337406139378906...

%t xi = x /. FindRoot[x + Tan[x] == 0, {x, 2}, WorkingPrecision -> 100]; RealDigits[(Pi/xi)^2] // First

%Y Cf. A196504.

%K nonn,cons,easy

%O 1,1

%A _Jean-François Alcover_, Jun 24 2014