a(0)=0 and a(1)=1, continued such that absolute values of 2nd differences equal the original sequence.
0, 1, 2, 2, 4, 4, 8, 8, 16, 16, 32, 32, 64, 64, 128, 128, 256, 256, 512, 512, 1024, 1024
1 seqfan posts
Sun Sep 13 18:42:04 CEST 2009 [seqfan] Re: Duplicates