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 A017203 #22 Dec 30 2024 22:43:13
%S A017203 2187,35831808,1801088541,21870000000,137231006679,587068342272,
%T A017203 1954897493193,5455160701056,13348388671875,29509034655744,
%U A017203 60170087060757,114868566764928,207616015289871,358318080000000,594467302491009,953133216331392,1483273860320763,2248392813428736
%N A017203 a(n) = (9*n + 3)^7.
%H A017203 Vincenzo Librandi, <a href="/A017203/b017203.txt">Table of n, a(n) for n = 0..10000</a>
%H A017203 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (8,-28,56,-70,56,-28,8,-1).
%F A017203 From _Amiram Eldar_, Oct 03 2024: (Start)
%F A017203 a(n) = A017197(n)^7 = 3^7 * A016783(n).
%F A017203 Sum_{n>=0} 1/a(n) = 28*Pi^7/(215233605*sqrt(3)) + 1093*zeta(7)/4782969. (End)
%t A017203 Table[(9*n + 3)^7, {n, 0, 20}] (* _Amiram Eldar_, Oct 03 2024 *)
%o A017203 (Magma) [(9*n+3)^7: n in [0..20]]; // _Vincenzo Librandi_, Jul 23 2011
%Y A017203 Cf. A013665, A016783, A017197.
%K A017203 nonn,easy
%O A017203 0,1
%A A017203 _N. J. A. Sloane_