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 A344442 #14 Dec 06 2024 11:28:55
%S A344442 0,1,1,4,1,6,1,10,5,8,1,20,1,10,9,23,1,24,1,28,11,14,1,48,7,16,17,36,
%T A344442 1,42,1,49,15,20,13,76,1,22,17,68,1,54,1,52,39,26,1,108,9,46,21,60,1,
%U A344442 78,17,88,23,32,1,132,1,34,49,102,19,78,1,76,27,74,1,180,1,40,53,84,19,90,1,154,54,44,1,172,23,46
%N A344442 a(n) = A332844(n) - n.
%H A344442 Antti Karttunen, <a href="/A344442/b344442.txt">Table of n, a(n) for n = 1..10080</a>
%H A344442 Antti Karttunen, <a href="/A344442/a344442.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%F A344442 a(n) = A332844(n) - n.
%F A344442 a(n) = Sum_{d|n} A000010(n/d) * (A124315(d)-1).
%F A344442 Sum_{k=1..n} a(k) ~ c * n^2 / 2, where c = Pi^6/540 - 1 = 0.7803503... . - _Amiram Eldar_, Dec 04 2024
%t A344442 Table[DivisorSum[n, Boole[IntegerQ[(n/#)^(1/2)]] DivisorSigma[1, #] &] - n, {n, 86}] (* _Michael De Vlieger_, May 24 2021 *)
%o A344442 (PARI)
%o A344442 A332844(n) = sumdiv(n,d, issquare(n/d) * sigma(d));
%o A344442 A344442(n) = (A332844(n) - n);
%Y A344442 Cf. A000010, A124315, A332844.
%K A344442 nonn
%O A344442 1,4
%A A344442 _Antti Karttunen_, May 23 2021