Be careful with that on 32-bit platforms, since on 32-bit platforms 1 << 33 will be 2

... when perl is not built with 64-bit integer support (here it is "v5.8.8 built for i386-freebsd-64int" (32 bit architecture)) ...

perl -we 'print map { sprintf "%d  %d\n" , $_ , ( 1 << $_ ) } ( 30 .. 
+34 , 60 .. 65 ) '
30  1073741824
31  2147483648
32  4294967296
33  8589934592
34  17179869184
60  1152921504606846976
61  2305843009213693952
62  4611686018427387904
63  -9223372036854775808
64  1
65  2
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