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 A134723 #12 Mar 27 2022 18:47:02
%S A134723 3,57,111317,19232931,3741434753,596167717379,838997101103107109,
%T A134723 113127131137139149151157,163167173179181191193197199,
%U A134723 211223227229233239241251257263,269271277281283293307311313317331
%N A134723 Concatenation of next n odd primes.
%H A134723 Vincenzo Librandi, <a href="/A134723/b134723.txt">Table of n, a(n) for n = 1..100</a>
%t A134723 Module[{nterms=12,max},max=(nterms(nterms+1))/2+1; FromDigits[ Flatten[ IntegerDigits/@#]]&/@ With[ {pr=Prime[Range[2,max]]},Table[Take[pr, {(n(n-1))/2+1,(n(n+1))/2}],{n,nterms}]]] (* _Harvey P. Dale_, Nov 25 2012 *)
%t A134723 Module[{nn=20},FromDigits[Flatten[IntegerDigits/@#]]&/@TakeList[Prime[ Range[ 2,(nn(nn+1))/2+1]],Range[nn]]] (* _Harvey P. Dale_, Mar 27 2022 *)
%Y A134723 Cf. A065091, A133013.
%K A134723 base,easy,nonn
%O A134723 1,1
%A A134723 _Omar E. Pol_, Nov 10 2007