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 A090879 #10 Oct 18 2020 08:00:18
%S A090879 1,4,7,20,21,94,71,328,457,1194,1035,7052,4109,17294,33807,83984,
%T A090879 65553,389650,262163,1484820,1949717,4216854,4194327,29409304,
%U A090879 22020121,67215386,119799835,350453788,268435485,1755807774,1073741855
%N A090879 a(n) = Sum_{d|n} d*2^(n-d).
%H A090879 Vaclav Kotesovec, <a href="/A090879/b090879.txt">Table of n, a(n) for n = 1..3000</a>
%F A090879 G.f.: Sum_{m>0} m*x^m/(1-(2*x)^m).
%t A090879 f[n_] := Block[{d = Divisors[n]}, Apply[Plus, d*2^(n - d)]]; Table[ f[n], {n, 1, 32}] (* _Robert G. Wilson v_, Feb 16 2004 *)
%Y A090879 Cf. A074854, A083413.
%K A090879 easy,nonn
%O A090879 1,2
%A A090879 _Vladeta Jovovic_, Feb 14 2004
%E A090879 More terms from _Robert G. Wilson v_, Feb 16 2004