What is "contraharmonic mean"

n. (context mathematics English) A type of average calculated as the arithmetic mean of the squares of the values divided by the arithmetic mean of the values, ie. $C\; =\; \{\; \{(\; x\_1^2\; +\; x\_2^2\; +\; ...\; +\; x\_n^2)\; over\; n\; \}\; over\; \{\; (\; x\_1\; +\; x\_2\; +\; ...\; +\; x\_n\; )\; over\; n\; \}\; \}\; or\; C(x\_1,\; x\_2,\; ...,\; x\_n)\; =\{\; \{\; x\_1^2+x\_2^2+...+x\_n^2\}\; over\; \{x\_1+x\_2+...+x\_n\; \}\}$

In mathematics, a contraharmonic mean is a function complementary to the harmonic mean. The contraharmonic mean is a special case of the Lehmer mean, L, where p=2.