for (my $i = 1; $i < \xFFFF; $i <<= 1)
 { print round($i+0.555,2), "  "; }
# which prints:

#1.56  2.56  4.55  8.55  16.56  32.56  64.56  128.56  256.56  512.55
#1024.56  2048.55  4096.56  8192.56  16384.56  32768.56  65536.55
#131072.55  262144.55  524288.56  1048576.55  2097152.56  4194304.55
#8388608.55  16777216.56
#
#(You can try with different numbers and different precision as long
# as the last digit is '5' and the precision = number of digits - 1)