Depending on your requirements on time and memory complexity, you could also use a hash

 DB<28> %in = map { $_ => 1 } 1,2,5,6,9,10,41..56

 DB<29> p $in{5}
1
 DB<30> p $in{0}

 DB<31>
[download]

update

corrected C&P error omitting the 1