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 A013930 #14 Mar 07 2021 03:14:12 %S A013930 1,2,3,4,5,7,9,11,13,15,17,19,20,23,25,26,27,29,32,34,37,40,41,42,43, %T A013930 44,46,47,49,50,51,53,54,56,58,60,61,63,64,65,69,70,71,74,76,77,79,80, %U A013930 81,82,83,84,86,88,89,90,92,94,95,96,98,100,102,103,104,106,107,108,110,111 %N A013930 Sum of first a(n) squarefrees is squarefree. %H A013930 Amiram Eldar, <a href="/A013930/b013930.txt">Table of n, a(n) for n = 1..10000</a> %t A013930 Position[Accumulate[Select[Range[200], SquareFreeQ]], _?SquareFreeQ, Heads -> False] // Flatten (* _Amiram Eldar_, Mar 07 2021 *) %Y A013930 Cf. A005117, A013931, A013932. %K A013930 nonn %O A013930 1,2 %A A013930 _Henri Lifchitz_ %E A013930 More terms from _David W. Wilson_