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 A014686 #13 Oct 04 2019 09:37:28
%S A014686 3,2,6,6,12,12,18,18,24,28,32,36,42,42,48,52,60,60,68,70,74,78,84,88,
%T A014686 98,100,104,106,110,112,128,130,138,138,150,150,158,162,168,172,180,
%U A014686 180,192,192,198,198,212,222,228,228,234,238,242,250,258,262,270,270
%N A014686 In sequence of prime numbers add 1 to first prime, 3rd prime, fifth prime, ... then subtract 1 from 2nd prime, fourth prime, sixth prime and so on.
%H A014686 Harvey P. Dale, <a href="/A014686/b014686.txt">Table of n, a(n) for n = 1..1000</a>
%F A014686 a(n)=prime(n)-(-1)^n=A000040(n)-A033999(n+1). [From _Juri-Stepan Gerasimov_, Sep 11 2009]
%t A014686 Module[{nn=60},Total/@Partition[Riffle[Prime[Range[nn]],{1,-1},{2,-1,2}],2]] (* _Harvey P. Dale_, Oct 04 2019 *)
%K A014686 nonn,easy
%O A014686 1,1
%A A014686 _Mohammad K. Azarian_
%E A014686 More terms from Andrew J. Gacek (andrew(AT)dgi.net)