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 A057523 #13 Feb 23 2024 07:10:37 %S A057523 1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1, %T A057523 1,1,1,2,1,2,1,1,1,1,2,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1, %U A057523 1,2,1,2,1,1,1,1,1,1,1,2,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,2,1,1,1,2,1,1,1,1,1 %N A057523 Number of ways n-th powerful (1) number can be expressed as b^2*c^3. %C A057523 Always positive. (Would be zero for any non-powerful number.) %C A057523 The positive terms of A370256. - _Amiram Eldar_, Feb 23 2024 %H A057523 Amiram Eldar, <a href="/A057523/b057523.txt">Table of n, a(n) for n = 1..10000</a> %F A057523 From _Amiram Eldar_, Feb 23 2024: (Start) %F A057523 a(n) = A370256(A001694(n)). %F A057523 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = zeta(3). (End) %e A057523 a(40) = 2 since the 40th powerful number is 576 = 24^2*1^3 = 3^2*4^3. %t A057523 f[p_, e_] := Floor[(e + 2)/2] - Floor[(e + 2)/3]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Array[s, 10000], # > 0 &] (* _Amiram Eldar_, Feb 23 2024 *) %o A057523 (PARI) lista(kmax) = {my(e); for(k = 1, kmax, e = factor(k)[, 2]; if(k == 1 || vecmin(e) > 1, print1(vecprod(apply(x -> (x+2)\2 - (x+2)\3, e)), ", ")));} \\ _Amiram Eldar_, Feb 23 2024 %Y A057523 Cf. A001694, A002117, A370256. %K A057523 nonn,easy %O A057523 1,11 %A A057523 _Henry Bottomley_, Sep 02 2000