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 A133017 #10 Dec 16 2021 16:32:14
%S A133017 1,2,3,4,5,7,8,9,1,0,1,1,1,2,1,3,1,4,1,5,1,6,1,7,1,8,1,9,2,0,2,1,2,2,
%T A133017 2,3,2,4,2,5,2,6,2,7,2,9,3,0,3,1,3,2,3,3,3,4,3,5,3,6,3,7,3,8,3,9,4,0,
%U A133017 4,1,4,2,4,3,4,4,4,5
%N A133017 Decimal expansion of the constant formed by concatenating the imperfect numbers.
%C A133017 A theorem of Copeland & Erdős proves that this constant is 10-normal. - _Charles R Greathouse IV_, Feb 06 2015
%H A133017 Harvey P. Dale, <a href="/A133017/b133017.txt">Table of n, a(n) for n = 0..1000</a>
%H A133017 A. H. Copeland and P. Erdős, <a href="http://www.renyi.hu/~p_erdos/1946-01.pdf">Note on normal numbers</a>, Bull. Amer. Math. Soc. 52 (1946), pp. 857-860.
%e A133017 0.12345789101112131415161718192021222324252627293031...
%t A133017 Flatten[IntegerDigits/@Table[If[PerfectNumberQ[n],Nothing,n],{n,70}]] (* _Harvey P. Dale_, Dec 16 2021 *)
%o A133017 (PARI) print1(1); for(n=2, 45, if(sigma(n,-1)!=2, d=digits(n); for(i=1, #d, print1(", "d[i])))) \\ _Charles R Greathouse IV_, Feb 06 2015
%Y A133017 Cf. A007376, A033307, A033308, A079718. Imperfect numbers: A132999.
%K A133017 cons,easy,nonn,base
%O A133017 0,2
%A A133017 _Omar E. Pol_, Oct 20 2007