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Search: id:A125521
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| A125521 |
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a(n) = minimal difference between two distinct n-digit with property that when one of them is typed into a calculator and rotated 180 degrees, the other one is seen. |
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+0
1
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OFFSET
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1,1
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FORMULA
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If n is even, a(n) is 6 followed by (n - 2) / 2 zeros. If n is odd, a(n) is 3 followed by (n - 1) / 2 zeros.
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EXAMPLE
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a(3) = 30. If one types 595 into a calculator and rotates it 180 degrees, they will get 565. 595 - 565 = 30. With a little thought, it is provable that 30 is the smallest possible difference.
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CROSSREFS
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Sequence in context: A136939 A136944 A136946 this_sequence A090932 A157534 A133799
Adjacent sequences: A125518 A125519 A125520 this_sequence A125522 A125523 A125524
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KEYWORD
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base,nonn
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AUTHOR
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Tanya Khovanova and Sergei Bernstein (tanyakh(AT)yahoo.com), Dec 29 2006
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