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 A099629 #5 Nov 30 2015 19:53:42 %S A099629 2,7,13,97,103,983,1039,9871,10243,98731,102359,987631,1023467, %T A099629 9876413,10234589,98765431,102345689,987654103 %N A099629 Smallest and largest primes pairwise displayed with k digits from k=1,...,9 with distinct decimal digits. %Y A099629 Cf. A098224-A098227. %K A099629 base,fini,full,nonn %O A099629 1,1 %A A099629 _Labos Elemer_, Oct 26 2004; corrected Oct 29 2004