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A202082
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In base-2 lunar arithmetic, a(n) is the smallest number that has exactly n different square roots (or -1 if no such number exists).
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1
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1, 111111111, 11111111111, 1011111111111111101, 1111111111111, 10111111111111111, 11100111111111111111111, 101111111111111111101, 111111111111111, 1011111111111111111, 1010111111111111111111101, 1110011111111111111111111, 10111111111111111111101, 11101111111111111111111, 11111111111111111, 1111111111111111111010000, 1111111111111111111111001
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OFFSET
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1,2
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COMMENTS
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The numbers are written in base 2.
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LINKS
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D. Applegate, M. LeBrun and N. J. A. Sloane, Dismal Arithmetic [Note: we have now changed the name from "dismal arithmetic" to "lunar arithmetic" - the old name was too depressing], Journal of Integer Sequences, Vol. 14 (2011), #11.9.8.
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EXAMPLE
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111111111 has two square roots, 11011 and 11111;
11111111111 has 3 square roots, 110111, 111011, 11111.
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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