for my $file (glob '1M01_F*.npt.gro') {
  next unless $file=~/^1M01_F\d{5}\.npt\.gro$/;
  print "$file\n";
}
__END__
1M01_F00121.npt.gro
1M01_F00130.npt.gro
1M01_F00140.npt.gro
1M01_F00150.npt.gro

##</code><code>##

for my $n (121,130,140,150) {
  my $file = sprintf '1M01_F%05d.npt.gro', $n;
  print "$file\n";
}
__END__
1M01_F00121.npt.gro
1M01_F00130.npt.gro
1M01_F00140.npt.gro
1M01_F00150.npt.gro