53位的回文平方数

Six years ago I wrote a program to search for palindromic square numbers and other palindromic numbers and found some new palindromic numbers. But with increasing length, the search became longer and longer so I finally gave it up.

Recently I got a new powerful machine with dual quad-core CPUs, so I brought it home during the Christmas and New Year holiday season. I modified my old search program to take advantage of multi-cores in the machine. The search program has tons of parallelism inside. Although the original code was written as incremental loops for performance reason, it is not hard to change it to run on multi-core system. The result is almost 8 fold improvement in speed, on top of CPU speed gain for the last six years.

With the multi-core version, I tried continuing the old quest again and find quite a few record breaking palindromic numbers during the holiday season. But I did not try to break the 52-digit palindromic square number record held by Pete Leadbetter since May 20, 2001 until last night. Before leaving work, I started searching for 53 digit paradromic sqaures and this morning we have a new record, a 53-digit palindromic square number:

122063831551139898460740721 ^ 2 = 14899578972945056149893218681239894165054927987599841

Other palindromic number records can be found at:

http://www.worldofnumbers.com/palrecs.htm

Go MultiCore!