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 A053998 #4 Mar 31 2012 10:32:39 %S A053998 2,3,29,101,229,421,673,1013,1429,1889,2441,3089,3821,4639,5521,6491, %T A053998 7577,8741,9941,11329,12757,14341,15881,17623,19477,21397,23333,25471, %U A053998 27743,30059,32441,34871,37507,40237,42953,46021 %N A053998 Smallest prime in n-th shell of prime spiral. %e A053998 a(2)=3 because it is the first prime in shell 1 (prime 2 is in shell 0). %K A053998 easy,nonn %O A053998 0,1 %A A053998 _Enoch Haga_, Apr 06 2000