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%I #16 Jan 19 2024 04:56:16
%S 0,1,5,14,39,75,124,224,345,514,710,935,1224,1585,2026,2510,3039,3715,
%T 4556,5456,6417,7506,8662,9887,11256,12700,14221,15902,17666,19515,
%U 21631,23840,26441,29250,32275,35524,38888,42369,46090,49934,54159
%N Sum of the squares of the first n squarefree numbers.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Squarefree.html">Squarefree</a>.
%F a(n) = Sum_{k=1..n} A005117(k)^2.
%F a(n) ~ c * n^3, where c = Pi^4/108 = 0.901936... . - _Amiram Eldar_, Jan 19 2024
%e a(10) = 1^2 + 2^2 + 3^2 + 5^2 + 6^2 + 7^2 + 10^2 + 11^2 + 13^2 + 14^2 = 710.
%t Join[{0},Accumulate[Select[Range[100],SquareFreeQ]^2]] (* _Harvey P. Dale_, Apr 08 2015 *)
%Y Cf. A005117.
%K nonn
%O 0,3
%A _Jonathan Vos Post_, Nov 17 2005
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