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A030990
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7-automorphic numbers ending in 3: final digits of 7n^2 agree with n.
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1
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3, 43, 143, 7143, 57143, 857143, 2857143, 42857143, 142857143, 7142857143, 57142857143, 857142857143, 2857142857143, 42857142857143, 142857142857143, 7142857142857143, 57142857142857143
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OFFSET
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1,1
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COMMENTS
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a(n) is the unique positive integer less than 10^n such that 7a(n) - 1 is divisible by 10^n. - Eric M. Schmidt, Aug 18 2012
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LINKS
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MATHEMATICA
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LinearRecurrence[{11, -10, -1000, 11000, -10000}, {3, 43, 143, 7143, 57143}, 20] (* Harvey P. Dale, Apr 02 2018 *)
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PROG
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(Sage) [inverse_mod(7, 10^n) for n in range(1, 1001)] # Eric M. Schmidt, Aug 18 2012
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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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