A030989 - OEIS

%I #24 Sep 22 2025 16:00:29

%S 6,96,896,4896,84896,184896,1184896,31184896,631184896,3631184896,

%T 13631184896,13631184896,13631184896,90013631184896,290013631184896,

%U 7290013631184896,57290013631184896,957290013631184896

%N 6-automorphic numbers: final digits of 6n^2 agree with n.

%C a(n) is the unique positive integer less than 10^n such that a(n) is divisible by 2^n and 6a(n) - 1 is divisible by 5^n. - _Eric M. Schmidt_, Aug 18 2012

%H Eric M. Schmidt, <a href="/A030989/b030989.txt">Table of n, a(n) for n = 1..1000</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AutomorphicNumber.html">Automorphic Number</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>

%o (SageMath) [crt(0, inverse_mod(6, 5^n), 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_