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 A134793 #4 Sep 10 2013 17:01:52
%S A134793 1,46,8910,12141516,1820212224,252627283032,33343536383940,
%T A134793 4244454648495051,525455565758606263,64656668697072747576,
%U A134793 7778808182848586878890,9192939495969899100102104105,106108110111112114115116117118119120121
%N A134793 Concatenation of next n nonprime numbers.
%t A134793 Module[{upto=35,comps,nn},nn=(upto(upto+1))/2;comps=Select[Range[nn], !PrimeQ[#]&];Table[FromDigits[Flatten[IntegerDigits/@Take[comps, {((i-1)(i))/2+1, (i(i+1))/2}]]],{i,25}]] (* _Harvey P. Dale_, Sep 10 2013 *)
%Y A134793 Cf. A053067, A133013. Nonprime numbers: A018252.
%K A134793 base,easy,nonn
%O A134793 1,2
%A A134793 _Omar E. Pol_, Nov 26 2007
%E A134793 More terms from _Harvey P. Dale_, Sep 10 2013