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 A030990 7-automorphic numbers ending in 3: final digits of 7n^2 agree with n. 1
 3, 43, 143, 7143, 57143, 857143, 2857143, 42857143, 142857143, 7142857143, 57142857143, 857142857143, 2857142857143, 42857142857143, 142857142857143, 7142857142857143, 57142857142857143 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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 LINKS Eric M. Schmidt, Table of n, a(n) for n = 1..1000 Eric Weisstein's World of Mathematics, Automorphic Number Index entries for linear recurrences with constant coefficients, signature (11,-10,-1000,11000,-10000). MATHEMATICA LinearRecurrence[{11, -10, -1000, 11000, -10000}, {3, 43, 143, 7143, 57143}, 20] (* Harvey P. Dale, Apr 02 2018 *) PROG (Sage) [inverse_mod(7, 10^n) for n in xrange(1, 1001)] # Eric M. Schmidt, Aug 18 2012 CROSSREFS Sequence in context: A003525 A042661 A281503 * A306970 A054698 A229695 Adjacent sequences:  A030987 A030988 A030989 * A030991 A030992 A030993 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified June 19 00:55 EDT 2019. Contains 324217 sequences. (Running on oeis4.)