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 A351395 #17 Feb 10 2022 08:30:07
%S A351395 1,3,4,7,6,12,8,15,13,18,12,16,14,24,24,31,18,21,20,22,32,36,24,24,31,
%T A351395 42,40,28,30,72,32,63,48,54,48,25,38,60,56,30,42,96,44,40,33,72,48,40,
%U A351395 57,43,72,46,54,48,72,36,80,90,60,76,62,96,41,127,84,144,68,58,96,144,72
%N A351395 Sum of the divisors of n that are either squarefree, prime powers, or both.
%H A351395 Michael De Vlieger, <a href="/A351395/b351395.txt">Table of n, a(n) for n = 1..10000</a>
%F A351395 a(n) = Sum_{d|n} d * sign(mu(d)^2 + [omega(d) = 1]).
%e A351395 a(36) = 25; 36 has 4 squarefree divisors 1,2,3,6 (where the primes 2 and 3 are both squarefree and 1st powers of primes) and 2 (additional) divisors that are powers of primes, 2^2 and 3^2. The sum of the divisors is then 1+2+3+4+6+9 = 25.
%t A351395 Array[DivisorSum[#, #*Sign[MoebiusMu[#]^2 + Boole[PrimeNu[#] == 1]] &] &, 71] (* _Michael De Vlieger_, Feb 10 2022 *)
%o A351395 (PARI) a(n) = sumdiv(n, d, if (issquarefree(d) || isprimepower(d), d)); \\ _Michel Marcus_, Feb 10 2022
%Y A351395 Cf. A001221, A008683, A246655.
%Y A351395 Sums of divisors: A048250 (squarefree), A023889 (prime powers), A008472 (prime).
%K A351395 nonn
%O A351395 1,2
%A A351395 _Wesley Ivan Hurt_, Feb 09 2022