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%I #22 Dec 07 2019 12:18:21
%S 5,25,125,8125,78125,578125,2578125,42578125,642578125,3642578125,
%T 83642578125,983642578125,1983642578125,51983642578125,
%U 251983642578125,1251983642578125,51251983642578125
%N 5-automorphic numbers: final digits of 5n^2 agree with n.
%C a(n) is the unique positive integer less than 10^n such that a(n) is divisible by 5^n and 5*a(n) - 1 is divisible by 2^n. - _Eric M. Schmidt_, Aug 18 2012
%H Eric M. Schmidt, <a href="/A030988/b030988.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a>
%H <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/AutomorphicNumber.html">Automorphic Number</a>
%o (Sage) [crt(inverse_mod(5, 2^n), 0, 2^n, 5^n) for n in range(1, 1001)] # _Eric M. Schmidt_, Aug 18 2012
%K nonn,base
%O 1,1
%A _Eric W. Weisstein_
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