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 A383008 #7 Apr 12 2025 09:41:59
%S A383008 2,5,7,10,15,17,19,22,25,28,30,36,39,41,44,47,49,51,54,59,63,66,69,72,
%T A383008 74,76,80,83,85,88,91,94,97,102,104,106,108,111,114,116,119,124,127,
%U A383008 129,132,135,138,140,143,148,151,156,159,161,164,169,171,173,176,178
%N A383008 Indices of the even terms in the sequence of squarefree numbers.
%C A383008 The asymptotic density of this sequence is 1/3.
%H A383008 Amiram Eldar, <a href="/A383008/b383008.txt">Table of n, a(n) for n = 1..10000</a>
%F A383008 A005117(a(n)) = A039956(n).
%F A383008 A373550(a(n)) = 0.
%t A383008 Position[Select[Range[350], SquareFreeQ], _?EvenQ] // Flatten
%o A383008 (PARI) list(lim) = {my(c = 0); for(k = 1, lim, if(issquarefree(k), c++; if(!(k % 2), print1(c, ", "))));}
%Y A383008 Cf. A005117, A039956, A071403, A373550, A383009.
%K A383008 nonn,easy
%O A383008 1,1
%A A383008 _Amiram Eldar_, Apr 12 2025