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 A075523 #4 Mar 30 2012 18:50:26 %S A075523 10,15,21,511,767,213,69,319,95,117,511,597,165,175,767,213,959,245, %T A075523 4351,287,1173,319,335,357,1557,405,415,1727,437,453,511,527,549,559, %U A075523 597,2431,629,655,671,693,46079,725,767,3093,789,799,847,895,3647,917 %N A075523 First nonprime reached when starting with the n-th prime p and iterating the map k -> 4*k+(p mod 4), or -1 if no integer is ever reached. %Y A075523 Cf. A075520, A075522, A075524. %K A075523 nonn %O A075523 1,1 %A A075523 _Reinhard Zumkeller_, Sep 19 2002