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 A013602 #18 Aug 13 2019 04:55:09
%S A013602 1,1,1,3,1,7,3,27,1,3,7,15,43,15,3,3,15,25,31,7,15,15,7,15,21,55,21,
%T A013602 159,81,69,33,135,13,9,33,25,15,37,15,7,13,9,3,27,7,133,25,129,61,7,
%U A013602 277,267,111,99,33,27,25,43,33,25,451,277,67,7,51,169,67,27,85,87
%N A013602 a(n) = nextprime(4^n)-4^n.
%H A013602 Daniel Starodubtsev, <a href="/A013602/b013602.txt">Table of n, a(n) for n = 0..1000</a>
%F A013602 a(n) = A104082(n) - A000302(n). - _Michel Marcus_, Aug 13 2019
%F A013602 a(n) = A013597(2*n), n >= 0. - _A.H.M. Smeets_, Aug 13 2019
%p A013602 seq(nextprime(4^i)-4^i,i=0..100);
%t A013602 np4[n_]:=Module[{c=4^n},NextPrime[c]-c]; Array[np4,70,0] (* _Harvey P. Dale_, Jan 23 2012 *)
%o A013602 (PARI) a(n) = nextprime(4^n)-4^n; \\ _Michel Marcus_, Aug 13 2019
%Y A013602 Cf. A000302, A104082.
%K A013602 nonn
%O A013602 0,4
%A A013602 James Kilfiger (mapdn(AT)csv.warwick.ac.uk)