or download this
C:\test\C>bitstrstr "DeBruijn(2^31).bin" 1048576 1 250000000
v:00000000008E0040 fsize:0000000010000004 vsize:2000000
...
bitstrstr5: 1500000000 : 1500000000 took:6.085954e-003 secs
bitstrstr5: 1750000000 : 1750000000 took:8.395146e-003 secs
bitstrstr5: 2000000000 : 2000000000 took:7.613071e-003 secs