harmonic number

Noun

 * 1)  Any of a series of numbers formed from the sum of the reciprocals of consecutive natural numbers
 * The fourth harmonic number has a value of $$H_3 =\sum_{k=1}^3 \frac{1}{k} =\frac{1}{1}+\frac{1}{2}+\frac{1}{3} =1\frac{5}{6} .$$

Translations

 * Italian: numero armonico
 * Japanese: 調和数