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A030991 7-automorphic numbers ending in 5: final digits of 7n^2 agree with n. 1
5, 75, 375, 4375, 84375, 984375, 8984375, 58984375, 458984375, 5458984375, 45458984375, 845458984375, 2845458984375, 22845458984375, 322845458984375, 2322845458984375, 22322845458984375 (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 5^n and 7a(n) - 1 is divisible by 2^n. - Eric M. Schmidt, Aug 18 2012

LINKS

Eric M. Schmidt, Table of n, a(n) for n = 1..1000

Index entries for sequences related to automorphic numbers

Index entries for sequences related to final digits of numbers

Eric Weisstein's World of Mathematics, Automorphic Number

PROG

(Sage) [crt(inverse_mod(7, 2^n), 0, 2^n, 5^n) for n in xrange(1, 1001)] # Eric M. Schmidt, Aug 18 2012

CROSSREFS

Sequence in context: A156703 A285452 A048350 * A216093 A151752 A127212

Adjacent sequences:  A030988 A030989 A030990 * A030992 A030993 A030994

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein

STATUS

approved

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Last modified November 22 13:47 EST 2019. Contains 329393 sequences. (Running on oeis4.)