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 A089923 #9 Jul 04 2024 03:36:23
%S A089923 5,17,89,383
%N A089923 Duplicate of A100003.
%C A089923 Previous name: Largest prime in the reverse concatenation of the first n consecutive prime numbers when that concatenation is a prime.
%e A089923 53 is the reverse concatenation of the consecutive primes 3 and 5. 53 is prime.
%o A089923 (PARI) revprime2(n) = { y=3; forprime(x=5,n, y=concat(Str(x),Str(y)); z=eval(y); if(ispseudoprime(z),print(x","z)) ) }
%K A089923 dead
%O A089923 5,1
%A A089923 _Cino Hilliard_, Jan 11 2004
%E A089923 Edited by _T. D. Noe_, Oct 30 2008