This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A106439 #15 May 08 2015 16:49:09
%S A106439 1,10,11,13,16,17,21,23,41,43,56,58,74,81,91,97,100,101,106,110,111,
%T A106439 113,115,121,122,130,131,137,142,155,157,161,170,171,172,178,179,181,
%U A106439 184,188,193,201
%N A106439 Belgian-1 numbers.
%H A106439 Reinhard Zumkeller, <a href="/A106439/b106439.txt">Table of n, a(n) for n = 1..10000</a>
%t A106439 belgianQ[n_, k_] := If[n < k, False, Block[{id = Join[{0}, IntegerDigits@ n]}, MemberQ[ Accumulate@ id, Mod[n - k, Plus @@ id]] ]]; Select[ Range@ 202, belgianQ[#, 1] &] (* _Robert G. Wilson v_, May 06 2011 *)
%o A106439 (Haskell)
%o A106439 a106439 n = a106439_list !! (n-1)
%o A106439 a106439_list = filter belge1 [1..] where
%o A106439 belge1 x = x == (head $ dropWhile (< x) $
%o A106439 scanl (+) 1 $ cycle (map (read . return) $ show x))
%o A106439 -- _Reinhard Zumkeller_, May 08 2015
%Y A106439 See A106039 for definition and link.
%Y A106439 Belgian-k numbers, k=0..9: A106039, A106439, A106518, A106596, A106631, A106792, A107014, A107018, A107032, A107043.
%Y A106439 Cf. A257770.
%K A106439 base,easy,nonn
%O A106439 1,2
%A A106439 _Eric Angelini_, Jun 07 2005