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 A100003 #21 Jul 16 2021 11:34:31
%S A100003 3,5,17,89,383,8831
%N A100003 Prime numbers p such that the concatenation of all odd primes up through p in decreasing order is prime.
%C A100003 Next term is greater than 4400th prime and the prime corresponding to the next term has more than 20000 digits. Number of digits of primes corresponding to the six known terms of the sequence are respectively 1, 2, 9, 43, 198, 4202.
%C A100003 We can see the prime corresponding to 383 (the 5th term of the sequence) in the page related to puzzle 8 of the website of Carlos Rivera.
%C A100003 a(7) > prime(28800) = 335033. - _Giovanni Resta_, Apr 01 2013
%H A100003 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_008.htm">Puzzle 8. Primes by Listing</a>, The Prime Puzzles and Problems Connection.
%e A100003 17 is in the sequence because 17.13.11.7.5.3 is prime (dot between numbers means concatenation).
%t A100003 Do[If[PrimeQ[(v={};Do[v=Join[v, IntegerDigits[Prime[n-j+1]]], {j, n-1}];FromDigits[v])], Print[Prime[n]]], {n, 2, 4413}]
%t A100003 Prime[#]&/@Select[Range[100],PrimeQ[FromDigits[Flatten[IntegerDigits/@ Prime[Range[#,2,-1]]]]]&] (* To generate a(6) increase the Range by 1000, but the program will run a long time. *) (* _Harvey P. Dale_, Nov 27 2015 *)
%Y A100003 Cf. A046284, A099070, A099071, A099073.
%Y A100003 The actual prime concatenations in A092448 and the original concatenations in A092447. - _Dmitry Kamenetsky_, Mar 02 2009
%K A100003 base,more,nonn,nice
%O A100003 1,1
%A A100003 _Farideh Firoozbakht_, Nov 06 2004