MathDB
I know it's only Power Mean but bear with me.. [ILL 1971]

Source:

January 1, 2011
inequalitiesinductioninequalities proposed

Problem Statement

Show that for nonnegative real numbers a,ba,b and integers n2n\ge 2, an+bn2(a+b2)n\frac{a^n+b^n}{2}\ge\left(\frac{a+b}{2}\right)^n When does equality hold?