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 A366954 #5 Oct 29 2023 23:04:32
%S A366954 1,28,168,1854,19776,327152,1244416,27319968,178422816,22222222056,
%T A366954 2075415810048,308768621226000,12455031810211128,2469135782022242640,
%U A366954 197530862561779410288,21604938101329359719880,1821571286217135606177024,270250398197557076360997936
%N A366954 The sum of the divisors of the concatenation of 1,2,3,...,n.
%F A366954 a(n) = sigma(A007908(n)) = A000203(A007908(n)).
%e A366954 a(3)=168 because the divisors of 123 are {1, 3, 41, 123}.
%Y A366954 Cf. A007908, A000203, A110756, A075019, A075022.
%K A366954 nonn,base
%O A366954 1,2
%A A366954 _Sean A. Irvine_, Oct 29 2023