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 A160452 #3 Mar 31 2012 10:26:15 %S A160452 19,199,1999,1999999999999999999999999999 %N A160452 Invertible primes of the form 1 followed by a string of 9's. %C A160452 These are values in A055558 whose rotation by 180 degrees occurs in A092571. I have checked all the numbers that correspond to entries in A002957 and can confirm that the next term in this sequence, if it exists, is greater than 2*10^55347-1. [From _Dmitry Kamenetsky_, May 22 2009] %e A160452 1999, for instance, is a prime which rotated upside down through 180 degrees becomes the prime 6661. Hence 1999 is in the sequence. %Y A160452 Cf. A048890, A055558. %Y A160452 Cf. A092571, A002957. [From _Dmitry Kamenetsky_, May 22 2009] %K A160452 more,nonn,base %O A160452 1,1 %A A160452 _Lekraj Beedassy_, May 14 2009