ikegami's is a general solution for all cases, but would it be sufficient in non-extreme cases (i.e., not trying to generate 100-character strings from just two different characters and with no more than two sequential repeats) to just generate bunches of strings and throw away all that are non-compliant? 

>perl -wMstrict -le
"use List::Util qw(shuffle);
 my @set = qw(a b c d e f);
 my $len = 12;
 my $needed = shift;
 my @out;
 while (@out < $needed) {
   my $str = join '', shuffle((@set) x $len);
   push @out, grep !m{ (.)\1\1 }xms, $str =~ m{ .{$len} }xmsg;
   }
 @out = @out[-$needed .. -1];
 m{ (.)\1\1 }xms and die qq{3+ same: '$_'} for @out;
 printf qq{%3d: '$out[$_]' \n}, 1+$_ for 0 .. $#out;
" 5
  1: 'becaecdbbedc'
  2: 'afccbecefdca'
  3: 'fbffecacfeaa'
  4: 'ddbacddfafca'
  5: 'fbebdabadedc'

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In reply to Re: Random data generation. by AnomalousMonk
in thread Random data generation. by BrowserUk

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