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 A152279 #4 Jul 20 2015 03:52:08 %S A152279 1,8,69,574,5520,52155,502179,4882568,47709672,468269438,4610668567, %T A152279 45510662200,450072137956,4457717637910 %N A152279 Number of 7's among the digits of all n-digit primes. %Y A152279 Cf. A130817, A152272, A152273, A152274, A152275, A152276, A152277, A152278, A152280, A152281. %K A152279 base,nonn %O A152279 1,2 %A A152279 _Jon E. Schoenfield_, Dec 01 2008 %E A152279 a(12)-a(14) from _Giovanni Resta_, Jul 20 2015