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 A020516 #28 Sep 08 2022 08:44:45
%S A020516 7,127,5461,299593,17895697,1108378657,69810262081,4432676798593,
%T A020516 282578800148737,18049651735527937,1154048505100108801,
%U A020516 73823022692637345793,4723519685917965029377,302268352895954163081217
%N A020516 Sum of n-th powers of divisors of 64.
%C A020516 7th cyclotomic polynomial evaluated at powers of 2.
%H A020516 T. D. Noe, <a href="/A020516/b020516.txt">Table of n, a(n) for n = 0..200</a>
%F A020516 G.f.: (-7+762 x-26670 x^2+377952 x^3-2267712 x^4+5462016 x^5-4161536 x^6)/(-1+127 x-5334 x^2+94488 x^3-755904 x^4+2731008 x^5-4161536 x^6+2097152 x^7). - _Harvey P. Dale_, Mar 21 2011
%F A020516 a(n) = (2^(7*n) - 1)/( 2^n - 1). Exp( Sum_{n >= 1} a(n)*x^n/n ) = 1 + 127*x + 10795*x^2 + ... is the o.g.f. for the 6th subdiagonal of triangle A022166, essentially A022189. - _Peter Bala_, Apr 07 2015
%p A020516 with(numtheory,cyclotomic):seq(cyclotomic(7,2^i),i=0..24);
%t A020516 Total[#^Range[0,15]&/@Divisors[64]] (* _Harvey P. Dale_, Mar 21 2011 *)
%o A020516 (Magma) [&+[Divisors(64)[i]^n: i in [1..7]]: n in [0..15]]; // _Vincenzo Librandi_, Apr 17 2014
%o A020516 (PARI) a(n) = polcyclo(7, 2^n); \\ _Michel Marcus_, Nov 13 2016
%Y A020516 Cf. A022166, A022189.
%K A020516 nonn,easy
%O A020516 0,1
%A A020516 _Simon Plouffe_