Wolstenholme number
A Wolstenholme number is a number that is the numerator of the generalized harmonic number Hn,2.
The first such numbers are 1, 5, 49, 205, 5269, 5369, 266681, 1077749, ….
These numbers are named after Joseph Wolstenholme, who proved Wolstenholme's theorem on modular relations of the generalized harmonic numbers.