Kofman, Rafael Moiseevich
Loshinski, Lev Ilich
1st HM., Problem (Zagreb), 1957
#3
9 + 12
There are these versions: 256602
Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) &
CSS/Javascript (jQuery, Bootstrap & DataTables).