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 A013932 #23 Aug 19 2025 05:22:50
%S A013932 1,3,6,11,17,34,58,87,123,166,215,274,305,407,482,521,562,647,791,899,
%T A013932 1073,1261,1327,1394,1463,1533,1677,1751,1906,1985,2067,2235,2321,
%U A013932 2497,2681,2870,2967,3170,3273,3378,3810,3921,4034,4381,4622,4745,5001,5131,5262
%N A013932 Integers that are squarefree and also the sum of first k squarefrees for some k.
%H A013932 Amiram Eldar, <a href="/A013932/b013932.txt">Table of n, a(n) for n = 1..10000</a>
%F A013932 a(n) = A005117(A020643(n)). - _Amiram Eldar_, Aug 19 2025
%t A013932 Select[Accumulate[Select[Range[150],SquareFreeQ]],SquareFreeQ] (* _Harvey P. Dale_, Jul 27 2011 *)
%o A013932 (PARI) lista(nn) = {my(s=0); for(k=1, nn, if(issquarefree(k)==1, s+=k; if(issquarefree(s)==1, print1(s, ", ")))); } \\ _Jinyuan Wang_, Feb 26 2020
%Y A013932 Cf. A005117, A013930, A013931, A020643, A173143.
%K A013932 nonn
%O A013932 1,2
%A A013932 _Henri Lifchitz_
%E A013932 More terms from _Jinyuan Wang_, Feb 26 2020