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 A344404 #20 Jun 13 2025 08:19:35
%S A344404 1,2,3,5,5,7,7,10,10,12,11,16,13,17,16,21,17,24,19,26,23,27,23,33,26,
%T A344404 32,30,36,29,41,31,42,36,42,36,52,37,47,43,53,41,57,43,57,51,57,47,69,
%U A344404 50,64,56,68,53,74,57,74,63,72,59,87,61,77,71,85,67,90,67,89,76,90,71
%N A344404 a(n) = Sum_{d|n} floor(n/d^2).
%F A344404 a(p) = Sum_{d|p} floor(p/d^2) = p + 0 = p, for prime p.
%F A344404 a(p^k) = Sum_{i=1..floor(k/2)+1} p^(k-2*i+2), where p is prime and k is a positive integer.
%F A344404 G.f.: Sum_{k>=1} x^(k^2)/((1 - x^k)*(1 - x^(k^2))). - _Miles Wilson_, Jun 11 2025
%t A344404 Table[Sum[(1 - Ceiling[n/k] + Floor[n/k]) Floor[n/k^2], {k, n}], {n, 100}]
%o A344404 (PARI) a(n) = sumdiv(n, d, n\d^2); \\ _Michel Marcus_, May 17 2021
%Y A344404 Cf. A344128, A344403, A344405.
%K A344404 nonn
%O A344404 1,2
%A A344404 _Wesley Ivan Hurt_, May 16 2021