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%I #8 Apr 08 2013 11:21:07
%S 1,51,751,8751,18751,218751,4218751,74218751,574218751,3574218751,
%T 63574218751,163574218751,163574218751,80163574218751,480163574218751,
%U 7480163574218751,87480163574218751,487480163574218751,5487480163574218751,15487480163574218751
%N (2*16^(5^n) - 1) mod 10^n: a sequence of trimorphic numbers ending in 1.
%C a(n) is the unique positive integer less than 10^n such that a(n) + 1 is divisible by 2^n and a(n) - 1 is divisible by 5^n.
%H Eric M. Schmidt, <a href="/A224474/b224474.txt">Table of n, a(n) for n = 1..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TrimorphicNumber.html">Trimorphic Number</a>
%H <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a>
%F a(n) = (2 * A016090(n) - 1) mod 10^n.
%o (Sage) def A224474(n) : return crt(-1, 1, 2^n, 5^n)
%Y Cf. A033819. Corresponding 10-adic number is A063006. The other trimorphic numbers ending in 1 are included in A199685 and A224476.
%K nonn,base
%O 1,2
%A _Eric M. Schmidt_, Apr 07 2013
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