 Similarly efficient strict functional or imperative sequential implementations are also possible whereas explicitly concurrent generative solutions might be non-trivial.In the Python programming language, lazy functional code for generating regular numbers is used as one of the built-in tests for correctness of the language's implementation.A related problem, discussed by , is to list all "k"-digit sexagesimal numbers in ascending order, as was done (for "k" = 6) by Inakibit-Anu, the Seleucid-era scribe of tablet AO6456.