Gregory's Formula
A series Leibniz, 
It converges very slowly, but its convergence can be accelerated using certain transformations, in particular
where
is the Riemann Zeta Function (Vardi 1991).See also Machin's Formula, Machin-Like Formulas, Pi
References
Vardi, I. Computational Recreations in Mathematica. Reading, MA: Addison-Wesley, pp. 157-158, 1991.
- Hedgehog
- Heegaard Diagram
- Heegaard Splitting
- Heegner Number
- Heesch Number
- Heesch's Problem
- Height
- Heilbronn Triangle Problem
- Heine-Borel Theorem
- Heine Hypergeometric Series
- Heisenberg Group
- Heisenberg Space
- Held Group
- Helen of Geometers
- Helicoid
- Helix
- Helly Number
- Helly's Theorem
- Helmholtz Differential Equation
- Helmholtz Differential Equation--Bipolar Coordinates
- Helmholtz Differential Equation--Cartesian Coordinates
- Helmholtz Differential Equation--Circular Cylindrical Coordinates
- Helmholtz Differential Equation--Confocal Ellipsoidal Coordinates
- Helmholtz Differential Equation--Confocal Paraboloidal Coordinates
- Helmholtz Differential Equation--Conical Coordinates