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 A101303 #10 Jan 21 2019 19:01:55
%S A101303 3,7,28,60,360,1512,3276,16256,65528,261120,79360,1098240,13852800,
%T A101303 25261824,79536128,1040179456,1710858240,13815410400,71687577600,
%U A101303 137707384824,151060010112,1932916285440,4212741841200,508764077015040,24560669041920,26379664917984
%N A101303 a(n) = sigma() [A000203] applied n times to prime(n).
%e A101303 a(1)= 3 = sigma(2);
%e A101303 a(2)= 7 = sigma(sigma(3));
%e A101303 a(3)= 28 = sigma(sigma(sigma(5)));
%e A101303 a(4)= 60 = sigma(sigma(sigma(sigma(7)))).
%p A101303 a:= n-> (numtheory[sigma]@@n)(ithprime(n)):
%p A101303 seq(a(n), n=1..30); # _Alois P. Heinz_, Oct 03 2018
%t A101303 f[n_] := DivisorSigma[1, n]; Table[ Nest[f, Prime[n], n], {n, 25}] (* _Robert G. Wilson v_, Dec 22 2004 *)
%Y A101303 Cf. A000203, A090896.
%K A101303 nonn,easy
%O A101303 1,1
%A A101303 _Jorge Coveiro_, Dec 22 2004
%E A101303 Edited and extended by _Robert G. Wilson v_, Dec 22 2004