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 A274004 #19 Aug 12 2016 06:21:40
%S A274004 3,3,4,5,5,6,6,7,7,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15,16,17,17,
%T A274004 18,18,19,19,20,20,21,21,22,22,23,23,24,24,25,25,26,26,27,27,28,28,29,
%U A274004 29,30,30,31,31,32,33,33,34,34,35,35
%N A274004 First differences of A002960.
%C A274004 The squared sieve sequence (A002960) increases by one, beginning with three, every two integers except a difference of 2^n appears only once. This is the sequence of first differences. This has not yet been proven in the general case.
%F A274004 Conjecture: a(n) = A274089(n+2). - _Omar E. Pol_, Aug 10 2016
%t A274004 Rest@ Differences@ Map[First, NestWhileList[Function[w, {First@ #, Rest@ #} &@ Delete[Last@ w, #] &@ Map[{#} &, Reverse@ Range[Floor@ Sqrt@ Length[Last@ w]]^2]], {0, Range@ 1200}, Length@ Last@ # > 1 &]] (* _Michael De Vlieger_, Aug 10 2016 *)
%Y A274004 Cf. A002960, A274089.
%K A274004 nonn
%O A274004 1,1
%A A274004 _Alisa Ediger_, Jun 06 2016