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 A321675 #16 Dec 20 2018 23:21:16
%S A321675 1,622,558275,549175530,548429473046,548320905633448,
%T A321675 548312690631798482,548311465139943768941,548311366911386862908968,
%U A321675 548311356554322895313137239,548311355740964925044531454428,548311355626818302486560961291870,548311355617569600726982364186141942
%N A321675 a(n) = Sum_{k=1..10^n} k*sigma(k).
%F A321675 a(n) = A143128(10^n).
%F A321675 a(n) ~ 10^(3*n) * Pi^2 / 18.
%t A321675 Array[Sum[k DivisorSigma[1, k], {k, 10^#}] &, 7, 0] (* _Michael De Vlieger_, Nov 20 2018 *)
%o A321675 (PARI) a(n) = sum(k=1, 10^n, k*sigma(k)); \\ _Michel Marcus_, Nov 23 2018
%Y A321675 Cf. A000203, A064987, A072692, A086463 (Pi^2/18), A143128.
%K A321675 nonn
%O A321675 0,2
%A A321675 _Daniel Suteu_, Nov 16 2018