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 A090518 #5 Dec 05 2013 19:56:38
%S A090518 5,11,83,769,3571,52631,1428571,3703703,83333333,769230769,5882352941,
%T A090518 13513513513,588235294117,7142857142857,12195121951219,
%U A090518 151515151515151,2777777777777777,22727272727272727,1111111111111111111
%N A090518 Primes arising in A090517, or 0 if A090517(n) = 0.
%C A090518 Conjecture: No term is zero.
%o A090518 (PARI) A090518(n)={ local(k,tenn) ; k=1 ; tenn=10^n ; while(1, if( isprime(floor(tenn/k)), return(floor(tenn/k)) ) ; k++ ; ) ; } { for(n=1,40, print1(A090518(n),",") ; ) } - _R. J. Mathar_, Nov 19 2006
%Y A090518 Cf. A090517, A090519, A090520.
%K A090518 base,nonn
%O A090518 1,1
%A A090518 _Amarnath Murthy_, Dec 07 2003
%E A090518 Corrected and extended by _R. J. Mathar_, Nov 19 2006