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 A130774 #9 May 08 2023 11:16:58
%S A130774 1,13,134,1347,134711,13471118,1347111829,134711182947,13471118294776,
%T A130774 13471118294776123,13471118294776123199,13471118294776123199322,
%U A130774 13471118294776123199322521,13471118294776123199322521843
%N A130774 Cumulative concatenation of A000204 Lucas numbers (beginning at 1).
%C A130774 a(2) = 13 and a(10) = 13471118294776123 are prime. What is the next prime?
%C A130774 The next prime is a(31), a number of 120 digits. - _Giovanni Resta_, Jun 18 2016
%F A130774 a(1) = 1; a(n+1) = Concatenate(a(n),A000204(n+1)).
%t A130774 Module[{nn=20,ll},ll=LucasL[Range[nn]];Table[FromDigits[Flatten[IntegerDigits/@Take[ll,n]]],{n,nn}]] (* _Harvey P. Dale_, May 07 2023 *)
%Y A130774 Cf. A000204.
%K A130774 base,easy,nonn
%O A130774 1,2
%A A130774 _Jonathan Vos Post_, Aug 19 2007