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 A256502 #12 Nov 13 2024 22:43:31
%S A256502 1,1,2,2,3,4,4,5,5,6,7,7,8,8,9,10,10,11,11,12,13,13,14,14,15,16,16,17,
%T A256502 18,18,19,19,20,21,21,22,22,23,24,24,25,25,26,27,27,28,28,29,30,30,31,
%U A256502 31,32,33,33,34,35,35,36,36,37,38,38,39,39,40,41,41
%N A256502 Largest integer not exceeding the harmonic mean of the first n squares.
%C A256502 Least k such that 1/k <= mean of {1, 1/2^2, 1/3^2,..., 1/n^2}.
%H A256502 Stanislav Sykora, <a href="/A256502/b256502.txt">Table of n, a(n) for n = 1..1000</a>
%F A256502 a(n) = floor(n/(Sum_{k=1..n} 1/k^2)).
%F A256502 Approaches asymptotically n/zeta(2), zeta being the Riemann function.
%F A256502 For any e > 0 and large enough n, n/zeta(2) + 36/Pi^4 - 1 < a(n) < n/zeta(2) + 36/Pi^4 + e. (Possibly this holds even with e = 0 for n > 29.) - _Charles R Greathouse IV_, Apr 08 2015
%t A256502 Table[Floor[HarmonicMean[Range[n]^2]],{n,70}] (* _Harvey P. Dale_, Mar 08 2020 *)
%o A256502 (PARI) \\ Using only precision-independent integer operations:
%o A256502 a(n)=(n*n!^2)\sum(k=1,n,(n!\k)^2)
%Y A256502 Cf. A226762.
%K A256502 nonn
%O A256502 1,3
%A A256502 _Stanislav Sykora_, Apr 08 2015