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 A319697 #14 Jun 30 2022 05:57:21 %S A319697 0,2,0,2,0,8,0,2,0,12,0,8,0,16,0,2,0,8,0,12,0,24,0,8,0,28,0,16,0,48,0, %T A319697 2,0,36,0,8,0,40,0,12,0,64,0,24,0,48,0,8,0,12,0,28,0,8,0,16,0,60,0,48, %U A319697 0,64,0,2,0,96,0,36,0,96,0,8,0,76,0,40,0,112,0,12,0,84,0,64,0,88,0,24,0,48,0,48,0,96 %N A319697 Sum of even squarefree divisors of n. %H A319697 Antti Karttunen, <a href="/A319697/b319697.txt">Table of n, a(n) for n = 1..20000</a> %F A319697 a(n) = Sum_{d|n} A059841(d)*A008966(d)*d. %F A319697 a(n) = A048250(n) - A206787(n). %t A319697 Table[Total[Select[Divisors[n],EvenQ[#]&&SquareFreeQ[#]&]],{n,100}] (* _Harvey P. Dale_, May 18 2019 *) %t A319697 f[2, e_] := 2; f[p_, e_] := p + 1; a[n_] := If[OddQ[n], 0, Times @@ f @@@ FactorInteger[n]]; Array[a, 100] (* _Amiram Eldar_, Jun 30 2022 *) %o A319697 (PARI) A319697(n) = sumdiv(n, d, (!(d%2))*issquarefree(d)*d); %Y A319697 Cf. A048250, A146076, A183063, A206787, A319698. %K A319697 nonn %O A319697 1,2 %A A319697 _Antti Karttunen_, Oct 31 2018