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%I #8 May 04 2026 00:36:38
%S 1,111,1,111,11211,111,1,111,11211,1123211,11211,111,1,111,11211,
%T 1123211,112343211,1123211,11211,111,1
%N An example of a stereogram: a flat picture that appears three-dimensional when viewed in the correct way.
%C What happens after 9? - _N. J. A. Sloane_, Nov 18 2006
%C Three-dimensionally it looks like this:
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000011232110000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000011232110000000000000000000000000000000...
%C ...000000000000000000000000000112343211000000000000000000000000000000...
%C ...000000000000000000000000000011232110000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000011232110000000000000000000000000000000...
%C ...000000000000000000000000000112343211000000000000000000000000000000...
%C ...000000000000000000000000001123454321100000000000000000000000000000...
%C ...000000000000000000000000000112343211000000000000000000000000000000...
%C ...000000000000000000000000000011232110000000000000000000000000000000...
%C ...000000000000000000000000000001121100000000000000000000000000000000...
%C ...000000000000000000000000000000111000000000000000000000000000000000...
%C ...000000000000000000000000000000010000000000000000000000000000000000...
%H Charles Ashbacher, <a href="https://fs.unm.edu/Ashbacher-book5.pdf">Smarandache Sequences, Stereograms and Series</a>, Phoenix, 2005, pp. 70-71.
%H Florentin Smarandache, <a href="https://fs.unm.edu/Sequences-book.pdf">Sequences of Numbers Involved in Unsolved Problems</a>, Hexis, Phoenix, 2006.
%Y Cf. A123698.
%K nonn
%O 1,2
%A Z. Wenpeng (wpzhang(AT)nwu.edu.cn), Nov 18 2006