A245261 - OEIS

%I #5 Jul 15 2014 13:01:02

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

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

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

%N Decimal expansion of the maximum of Planck's radiation function.

%H Eric Weisstein's MathWorld, <a href="http://mathworld.wolfram.com/PlancksRadiationFunction.html">Planck's Radiation Function</a>

%F (15*(W(-(5/e^5)) + 5)^5)/((-1 + exp(W(-(5/e^5)) + 5))*Pi^4), where W is the LambertW function (also known as ProductLog).

%e 3.2648034339755571402288131198557638278982761871385361958956956...

%t f[x_] := 15/(Pi^4*x^5*(Exp[1/x] - 1)); xmax = 1/(ProductLog[-5*Exp[-5]] + 5); RealDigits[f[xmax], 10, 105] // First

%Y Cf. A133838, A133839, A133840.

%K nonn,cons

%O 1,1

%A _Jean-François Alcover_, Jul 15 2014