De Bruijn's sequence: 2^(2^(n-1) - n): ways of arranging 2^n bits in circle so all 2^n consecutive strings of length n are distinct.
1, 1, 2, 16, 2048, 67108864, 144115188075855872
1 seqfan posts
Wed Apr 14 14:08:16 CEST 2010 [seqfan] Re: What is the difference between A000610 and A001320?