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 A073255 #17 Mar 10 2019 13:04:59
%S A073255 7,12,15,13,18,28,24,24,31,39,42,32,36,60,31,42,40,56,72,63,48,54,48,
%T A073255 91,60,56,90,96,84,78,72,124,57,93,72,98,120,72,120,80,90,168,96,104,
%U A073255 127,84,144,126,96,144,195,114,124,140,96,168,186,121,126,224,108,132
%N A073255 Sum of divisors of n-th composite number.
%H A073255 Robert Israel, <a href="/A073255/b073255.txt">Table of n, a(n) for n = 1..10000</a>
%F A073255 a(n) = A000203(A002808(n)).
%e A073255 First composite is 4, sigma[4]=1+2+4=7=a(1).
%p A073255 map(numtheory:-sigma, remove(isprime,[$4..100])); # _Robert Israel_, Aug 27 2018
%t A073255 c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Table[DivisorSigma[1, c[w]], {w, 1, 128}]
%t A073255 DivisorSigma[1,#]&/@(Select[Range[100],CompositeQ]) (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 10 2019 *)
%o A073255 (PARI) lista(nn) = forcomposite(c=1, nn, print1(sigma(c), ", ")); \\ _Michel Marcus_, Feb 21 2016
%Y A073255 Cf. A000203, A002808, A035004.
%K A073255 nonn
%O A073255 1,1
%A A073255 _Labos Elemer_, Jul 22 2002