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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 sequences related to automorphic numbers

Index entries for sequences related to final digits of numbers

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 * A054698 A229695 A060559

Adjacent sequences:  A030987 A030988 A030989 * A030991 A030992 A030993

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein

STATUS

approved

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Last modified October 20 15:14 EDT 2017. Contains 293612 sequences.