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 A345891 #10 Jun 29 2021 08:09:28
%S A345891 1,3,7,10,21,16,43,36,57,46,111,56,157,92,127,136,273,120,343,172,261,
%T A345891 232,507,208,505,326,495,352,813,262,931,528,673,562,851,456,1333,704,
%U A345891 951,664,1641,534,1807,904,1101,1036,2163,800,2065,1030,1651,1276,2757,1008,2215,1376
%N A345891 a(n) = n + (n - 1) * phi(n).
%C A345891 For 1 <= k <= n, add n if gcd(n,k) = 1, otherwise add 1. For n = 9 there are 6 numbers less than or equal to 9 that are relatively prime to 9 and 3 that are not. So a(9) = 9*6 + 3*1 = 57.
%F A345891 a(n) = Sum_{k=1..n} n^floor(1/gcd(n,k)).
%F A345891 a(n) = A062955(n) + n. - _Michel Marcus_, Jun 28 2021
%t A345891 Table[n + (n - 1)*EulerPhi[n], {n, 50}]
%o A345891 (PARI) a(n) = n + (n-1)*eulerphi(n); \\ _Michel Marcus_, Jun 28 2021
%Y A345891 Cf. A000010 (phi), A062955, A345892.
%K A345891 nonn
%O A345891 1,2
%A A345891 _Wesley Ivan Hurt_, Jun 28 2021