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 A152276 #4 Jul 20 2015 03:49:38 %S A152276 0,3,31,326,3412,35234,358468,3625027,36582450,368381208,3704525518, %T A152276 37218251329,373639701352,3748854986738 %N A152276 Number of 4's among the digits of all n-digit primes. %Y A152276 Cf. A130817, A152272, A152273, A152274, A152275, A152277, A152278, A152279, A152280, A152281. %K A152276 base,nonn %O A152276 1,2 %A A152276 _Jon E. Schoenfield_, Dec 01 2008 %E A152276 a(12)-a(14) from _Giovanni Resta_, Jul 20 2015