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 A111715 #17 Feb 16 2025 08:32:58
%S A111715 0,1,5,14,39,75,124,224,345,514,710,935,1224,1585,2026,2510,3039,3715,
%T A111715 4556,5456,6417,7506,8662,9887,11256,12700,14221,15902,17666,19515,
%U A111715 21631,23840,26441,29250,32275,35524,38888,42369,46090,49934,54159
%N A111715 Sum of the squares of the first n squarefree numbers.
%H A111715 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Squarefree.html">Squarefree</a>.
%F A111715 a(n) = Sum_{k=1..n} A005117(k)^2.
%F A111715 a(n) ~ c * n^3, where c = Pi^4/108 = 0.901936... . - _Amiram Eldar_, Jan 19 2024
%e A111715 a(10) = 1^2 + 2^2 + 3^2 + 5^2 + 6^2 + 7^2 + 10^2 + 11^2 + 13^2 + 14^2 = 710.
%t A111715 Join[{0},Accumulate[Select[Range[100],SquareFreeQ]^2]] (* _Harvey P. Dale_, Apr 08 2015 *)
%Y A111715 Cf. A005117.
%K A111715 nonn
%O A111715 0,3
%A A111715 _Jonathan Vos Post_, Nov 17 2005