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 A129808 #13 Nov 06 2015 02:00:07
%S A129808 1,4,6,8,9,1,0,1,2,1,4,1,5,1,6,1,8,2,0,2,1,2,2,2,4,2,5,2,6,2,7,2,8,3,
%T A129808 0,3,2,3,3,3,4,3,5,3,6,3,8,3,9,4,0,4,2,4,4,4,5,4,6,4,8,4,9,5,0,5,1,5,
%U A129808 2,5,4,5,5,5,6,5,7,5,8,6,0,6,2,6,3,6,4,6,5,6,6,6,8,6,9,7,0,7,2,7,4,7,5,7,6
%N A129808 Decimal expansion of constant equal to concatenated nonprimes.
%C A129808 A theorem of Copeland & Erdős proves that this constant is 10-normal. - _Charles R Greathouse IV_, Feb 06 2015
%H A129808 Demi Allen, Sky Brewer, <a href="http://arxiv.org/abs/1511.01789">Distribution Of Sequences Generated By Certain Simply-Constructed Normal Numbers</a>, arXiv:1511.01789 [math.NT], 2015.
%H A129808 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 A129808 1.468910121415161820212224252627283032333435363839404244454648495...
%t A129808 Flatten[IntegerDigits/@With[{nn=80},Complement[Range[nn],Prime[ Range[ PrimePi[nn]]]]]] (* _Harvey P. Dale_, Sep 16 2011 *)
%o A129808 (PARI) print1(1); forcomposite(n=4,76,d=digits(n); for(i=1,#d, print1(", "d[i]))) \\ _Charles R Greathouse IV_, Feb 06 2015
%Y A129808 Cf. A033308 (decimal expansion of Copeland-Erdos constant: concatenate primes).
%K A129808 cons,nonn,base
%O A129808 1,2
%A A129808 _Alexander Adamchuk_, May 19 2007