First, some definitions:
Not all numbers that fail to reach a palindrome count as Lychrel numbers, though. Many simply exist as a direct consequence of an earlier Lychrel number (such as 887, which results from 196+691=887). Others, like 295, do not themselves form part of a different Lychrel's iterations, but still join up with it at some point (295+592=887, imagine that!). So, of any given series of numbers iterated with the 196 algorithm, only the lowest number that leads to that series counts as a proper Lychrel number.
Okay, I know, you can find all of this much better explained elsewhere, and I'll give links to a few of them now (No exclusion of good web pages intended... If you think you have a page on par with one of these for quality of content, yet not totally redundant, let me know and I'll consider giving you a link)
As my contribution to the world of numerical palindromes, aside from writing a variety of useful Lychrel-related tools and holding a few current-and-past records myself, I have decided to run this 196-and-Lychrel-oriented source code repository.
Barry uses arbitrary-length integer routines to deal
with actual numbers, rather than strings of digits.
|Matthew Stenson||09/29/2004||F90 + asm||GPL2||
(archive includes v1)
The most recent (final?) version of Matt's iterator.
Added an assembly FAA routine for performance.
|Matthew Stenson||08/30/2003||C+MMX (VS)||GPL2||196xampl_vs.zip||
A port of my example code,
builds under Visual Studio 6 with MASM. Thanks!
|Matthew Stenson||08/19/2003||Fortran 90||GPL2||
(archive includes v3)
The first viable F90 implementation I've
ever seen. Uses a lookup-table appproach
|Eric Goldstein||03/22/2003||Inline P4 asm||PD||e_goldst.c||
The current speed-record holding
|Prosper & Veigneau||03/21/2003||C||PD?||vp_sg.c||
An arbitrary-base vanilla-C implementation.
Interesting optimizations, well worth studying
Windows GUI-mode version of the MOD-9
checker. Includes several data visualization tools
|Calin A. Culianu||08/20/2002||C++||GPL2||culianu.cpp||
A pure C++ version, quite readable,
allows calculations in an arbitrary base
Verifies a save point in Istvan's file
format, usign the MOD-9 checksum
|Benjamin Despres||06/28/2002||C + asm(MMX)||GPL2||196xampl.zip||
The once-fastest reverse-and-add code,
since superseded a few times.
Linux version, makes use of a
digit-at-a-time lookup table
The original, not all that fast,
but of unquestionable historic value
Those entries with a question mark in their status have an unknown official status, though for various reasons I assume them as released into the Public Domain. If you wrote one of these and wish it removed, contact me and I will immediately comply.