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 A104323 #8 Aug 02 2021 18:40:09
%S A104323 10987,22212019,86858483,94939291,100999897,106105104103,112111110109,
%T A104323 122121120119,124123122121,146145144143,184183182181,226225224223,
%U A104323 232231230229,244243242241,274273272271,332331330329,362361360359
%N A104323 Primes which are the reverse concatenation of four consecutive numbers.
%H A104323 Zak Seidov, <a href="/A104323/b104323.txt">Table of n, a(n) for n = 1..328</a>
%e A104323 The first term is 10987 which is a prime and is the reverse concatenation of 7,8,9 and 10 which are four consecutive numbers.
%t A104323 Select[Table[FromDigits[Flatten[IntegerDigits/@Range[n,n-3,-1]]],{n,4,400}],PrimeQ] (* _Harvey P. Dale_, Aug 02 2021 *)
%o A104323 (PARI) forstep(n=10,400,2,isprime(t=eval(Str(n,n-1,n-2,n-3)))&print1(t",")) \\ _Zak Seidov_, May 08 2013
%Y A104323 Cf. A052089.
%K A104323 base,nonn
%O A104323 1,1
%A A104323 _Shyam Sunder Gupta_, Apr 17 2005