Ramanujan had 17 beautiful formulas for pi which used class invariants. They were the inspiration for a related set of formulas found by the Chudnovsky brothers.
The modular function involved in the latter set of formulas is the j-function and its connection to the Monster group is well-known. The q-series of the function begins (1,744,196884...) and the Monster group is the group of rotations in 196883-dimensional space.
However, some of Ramanujan's formulas uses a modular function whose q-series starts as (1,104, 4372...) and the Baby Monster has an irreducible representation in 4371 dimensions.
We also provide new formulas using higher class numbers (since Ramanujan primarily used discriminants of class number 2).
For number theory, please jump to Page 9.
