eval a={1..9}\;b={1..9}' let z[$a$a]=$a$a z[$a$a$b]=z[$a$b$a]=z[$b$a$a]=$a$b$a z[a*101]=z[a*110]=a*101 z[$a$a$b$b]=z[$a$b$a$b]=z[$b$a$a$b]=b/a?$a$b$b$a:$b$a$a$b z[a*1001]=z[a*1010]=z[a*1100]=1001*a ' history -p {1..9} ${z[*]}