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 A345140 #4 Jun 09 2021 11:14:41
%S A345140 1,2,5,9,16,22,36,44,64,79,108,120,171,185,238,275,347,365,477,497,
%T A345140 624,687,820,844,1071,1113,1313,1410,1671,1701,2094,2126,2489,2636,
%U A345140 3020,3108,3732,3770,4288,4504,5192,5234,6151,6195,7046,7415,8284,8332,9702,9788,11007,11411,12759,12813,14639
%N A345140 a(1) = 1; a(n+1) = n + Sum_{d|n} a(d).
%F A345140 G.f. A(x) satisfies: A(x) = x * (1 + x / (1 - x)^2 + A(x) + A(x^2) + A(x^3) + ...).
%t A345140 a[1] = 1; a[n_] := a[n] = n - 1 + Sum[a[d], {d, Divisors[n - 1]}]; Table[a[n], {n, 1, 55}]
%t A345140 nmax = 55; A[_] = 0; Do[A[x_] = x (1 + x/(1 - x)^2 + Sum[A[x^k], {k, 1, nmax}]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x] // Rest
%Y A345140 Cf. A003238, A068336, A330575.
%K A345140 nonn
%O A345140 1,2
%A A345140 _Ilya Gutkovskiy_, Jun 09 2021