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 A064366 #28 Dec 14 2024 14:42:23
%S A064366 1,3,6,21,15,66,28,1365,1716,3060,66,20475,91,134596,735471,7888725,
%T A064366 153,3262623,190,118030185,225792840,254186856,276,2558620845,
%U A064366 84672315,11058116888,113380261800,558383307300,435,11969016345,496,366395202809685,16735679449896,21094923659355
%N A064366 a(n) = binomial(sigma(n), phi(n)).
%H A064366 Harry J. Smith, <a href="/A064366/b064366.txt">Table of n, a(n) for n = 1..200</a>
%F A064366 a(n) = binomial(A000203(n), A000010(n));
%F A064366 a(p) = A000217(p) for prime p.
%t A064366 Array[Binomial[DivisorSigma[1, #], EulerPhi@ #] &, 31] (* _Michael De Vlieger_, Nov 03 2017 *)
%o A064366 (PARI) a(n) = { binomial(sigma(n), eulerphi(n)) } \\ _Harry J. Smith_, Sep 12 2009
%Y A064366 Cf. A000010, A000203, A000217, A034953, A066090, A066449.
%K A064366 nonn
%O A064366 1,2
%A A064366 _Labos Elemer_, Sep 27 2001