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  • Doug Seelinger thinks this is interesting:

ln

From

Cover of Art of Computer Programming, The: Volume 1: Fundamental Algorithms

Note

Both refer to a logarithm, but the base for "ln" is the number e (a special number roughly equal to 2.1781) while the base for "log" is 10, unless otherwise specified. "ln" is called the natural logarithm and "log" is called the common logarithm when it refers to the base 10 logarithm