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 A074366 #20 Jan 20 2025 16:23:02
%S A074366 3,29,239,2371,235723,23571127,2357111357,235711131727,23571113171939,
%T A074366 2357111317192343,235711131719232977,23571113171923293283,
%U A074366 2357111317192329313801,235711131719232931374149,23571113171923293137414371,2357111317192329313741434781
%N A074366 The first prime greater than the concatenation of the first n primes.
%H A074366 Harvey P. Dale, <a href="/A074366/b074366.txt">Table of n, a(n) for n = 1..200</a>
%e A074366 The first prime > 235, the concatenation of the first three primes, is 239. Hence a(3) = 239.
%t A074366 p[n_] := Module[{r, i}, r = 2; i = 1; While[r <= n, i = i + 1; r = Prime[i]]; r]; s = ""; a = {}; Do[s = s <> ToString[Prime[i]]; a = Append[a, p[ToExpression[s]]], {i, 1, 8}]; a
%t A074366 <<NumberTheory`NumberTheoryFunctions` sz[x_] :=FromDigits[Flatten[Table[IntegerDigits[Prime[j]], {j, 1, x}], 1]] Table[NextPrime[sz[w]], {w, 1, 35}] (* _Labos Elemer_, Mar 18 2005 *)
%t A074366 Module[{nn=20,p},p=Prime[Range[nn]];Table[NextPrime[FromDigits[Flatten[ IntegerDigits/@Take[p,n]]]],{n,nn}]] (* _Harvey P. Dale_, Oct 03 2013 *)
%o A074366 (Python)
%o A074366 from sympy import nextprime, prime, primerange
%o A074366 def a(n):
%o A074366 return nextprime(int("".join(map(str, primerange(2, prime(n)+1)))))
%o A074366 print([a(n) for n in range(1, 17)]) # _Michael S. Branicky_, Mar 29 2021
%Y A074366 Cf. A019518.
%K A074366 nonn,base
%O A074366 1,1
%A A074366 _Joseph L. Pe_, Sep 26 2002
%E A074366 More terms from _Labos Elemer_, Mar 18 2005
%E A074366 Edited by _N. J. A. Sloane_, May 21 2008 at the suggestion of _R. J. Mathar_
%E A074366 Edited by _Charles R Greathouse IV_, Apr 28 2010