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 A262778 #9 Apr 04 2016 23:29:07 %S A262778 12,103,1005,10007,100011,1000013,10000017,100000019,1000000023, %T A262778 10000000029,100000000031,1000000000037,10000000000041, %U A262778 100000000000043,1000000000000047,10000000000000053,100000000000000059,1000000000000000061 %N A262778 a(n) = 10^n + prime(n). %e A262778 a(4) = 10^4+7=10007. %o A262778 (PARI) a(n) = 10^n + prime(n); \\ _Altug Alkan_, Mar 24 2016 %Y A262778 Cf. A000040, A011557. %K A262778 nonn %O A262778 1,1 %A A262778 _Emre APARI_, Mar 24 2016