Enumerating elements of the Eisenstein array
This is a Literate Haskell module with functions to enumerate the elements of the Eisenstein array. Also, we provide a program that searches for occurrences of the Eisenstein array on OEIS. (Joint work with Roland Backhouse.)
I suggest that you read the PDF version of the Literate Haskell program.
In 1858, A.M. Stern published a detailed study of a process of constructing an infinite sequence of numbers from a given pair of numbers. Stern attributed the process to Eisenstein, and the sequence of numbers is now known as the Eisenstein array.
In a recent paper , we review Stern's paper and briefly discuss algorithms that enumerate the elements of the Eisenstein Array. In this document we present several Haskell implementations of these algorithms.
 Roland C. Backhouse and João F. Ferreira. On Euclid's algorithm and elementary number theory. Sci. Comput. Program. (76:3), 2011. URL: http://joaoff.com/publications/2010/euclid-alg/