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A032123
Number of 2n-bead black-white reversible strings with n black beads.
+0
2
1, 1, 4, 10, 38, 126, 472, 1716, 6470, 24310, 92504, 352716, 1352540, 5200300, 20060016, 77558760, 300546630, 1166803110, 4537591960, 17672631900, 68923356788, 269128937220, 1052049834576, 4116715363800
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Maintained by
N. J. A. Sloane
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njas@research.att.com
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Last modified December 17 23:40 EST 2009. Contains 171025 sequences.
AT&T Labs Research
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