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%I #19 Feb 24 2024 01:04:07
%S 111,2112,31113,411114,5111115,61111116,711111117,8111111118,
%T 91111111119,10111111111110,111111111111111,1211111111111112,
%U 13111111111111113,141111111111111114,1511111111111111115,16111111111111111116,171111111111111111117,1811111111111111111118
%N a(n) = n concatenated with n 1's and n.
%C All terms are divisible by 3. - Donald Sampson (marsquo(AT)hotmail.com), Dec 09 2003
%D J. Earls, On Smarandache Repunit N Numbers, Smarandache Notions Journal
%D (2004), Vol. 14.1, pp 251-258.
%F a(n) = n * 10^(n+L) + 10^L * R + n, where R is the n-th repunit and L is the number of decimal digits of n.
%t Array[FromDigits@ Join[#1, #2, #1] & @@ {IntegerDigits[#], ConstantArray[1, #]} &, 16] (* _Michael De Vlieger_, Mar 21 2018 *)
%Y Cf. A075842, A075858.
%K base,easy,nonn,less
%O 1,1
%A _Jason Earls_, Oct 15 2002
%E More terms from Donald Sampson (marsquo(AT)hotmail.com), Dec 09 2003
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