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 A327527 #15 Dec 19 2023 09:19:55 %S A327527 1,2,2,3,2,4,2,4,3,4,2,5,2,4,4,5,2,5,2,5,4,4,2,6,3,4,4,5,2,8,2,6,4,4, %T A327527 4,7,2,4,4,6,2,8,2,5,5,4,2,7,3,5,4,5,2,6,4,6,4,4,2,9,2,4,5,7,4,8,2,5, %U A327527 4,8,2,8,2,4,5,5,4,8,2,7,5,4,2,9,4,4,4,6,2,9,4,5,4,4,4,8,2,5,5,7,2,8,2,6,8 %N A327527 Number of uniform divisors of n. %C A327527 A number is uniform if its prime multiplicities are all equal, meaning it is a power of a squarefree number. Uniform numbers are listed in A072774. The maximum uniform divisor of n is A327526(n). %H A327527 Antti Karttunen, <a href="/A327527/b327527.txt">Table of n, a(n) for n = 1..65537</a> %H A327527 Gus Wiseman, <a href="https://docs.google.com/document/d/e/2PACX-1vSX9dPMGJhxB8rOknCGvOs6PiyhupdWNpqLsnphdgU6MEVqFBnWugAXidDhwHeKqZe_YnUqYeGOXsOk/pub">Sequences counting and encoding certain classes of multisets</a>. %F A327527 From _Amiram Eldar_, Dec 19 2023: (Start) %F A327527 a(n) = A034444(n) + A368251(n). %F A327527 Sum_{k=1..n} a(k) ~ (n/zeta(2)) * (log(n) + 2*gamma - 1 - 2*zeta'(2)/zeta(2) + c * zeta(2)), where gamma is Euler's constant (A001620) and c = A368250. (End) %e A327527 The uniform divisors of 40 are {1, 2, 4, 5, 8, 10}, so a(40) = 6. %t A327527 Table[Length[Select[Divisors[n],SameQ@@Last/@FactorInteger[#]&]],{n,100}] %t A327527 a[n_] := Module[{e = FactorInteger[n][[;; , 2]]}, 1 + Total[2^Accumulate[Count[e, #] & /@ Range[Max[e], 1, -1]] - 1]]; a[1] = 1; Array[a, 100] (* _Amiram Eldar_, Dec 19 2023 *) %o A327527 (PARI) %o A327527 isA072774(n) = { ispower(n, , &n); issquarefree(n); }; \\ From A072774 %o A327527 A327527(n) = sumdiv(n,d,isA072774(d)); \\ _Antti Karttunen_, Nov 13 2021 %Y A327527 See link for additional cross-references. %Y A327527 Cf. A000005, A000961, A005117, A006530, A007947, A071625, A112798. %Y A327527 Cf. A072774, A327526. %Y A327527 Cf. A001620, A013661, A306016, A368250, A368251. %K A327527 nonn %O A327527 1,2 %A A327527 _Gus Wiseman_, Sep 17 2019 %E A327527 Data section extended up to 105 terms by _Antti Karttunen_, Nov 13 2021