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A030992 7-automorphic numbers ending in 8: final digits of 7n^2 agree with n. 1
8, 68, 768, 2768, 72768, 872768, 3872768, 83872768, 683872768, 1683872768, 11683872768, 11683872768, 11683872768, 20011683872768, 820011683872768, 4820011683872768, 34820011683872768, 534820011683872768 (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 a(n) is divisible by 2^n and 7a(n) - 1 is divisible by 5^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) [crt(0, inverse_mod(7, 5^n), 2^n, 5^n) for n in xrange(1, 1001)] # Eric M. Schmidt, Aug 18 2012

CROSSREFS

Sequence in context: A167859 A243246 A113357 * A091590 A303010 A087487

Adjacent sequences:  A030989 A030990 A030991 * A030993 A030994 A030995

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein

STATUS

approved

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Last modified June 24 21:16 EDT 2019. Contains 324337 sequences. (Running on oeis4.)