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 A304383 #19 May 16 2018 13:19:22 %S A304383 67,139,283,571,1147,2299,4603,9211,18427,36859,73723,147451,294907, %T A304383 589819,1179643,2359291,4718587,9437179,18874363,37748731,75497467, %U A304383 150994939,301989883,603979771,1207959547,2415919099,4831838203,9663676411,19327352827,38654705659,77309411323 %N A304383 a(n) = 36*2^n - 5 (n>=1). %C A304383 a(n) is the number of edges in the molecular graph NS2[n], defined pictorially in the Ashrafi et al. reference (Fig. 2, where NS2[2] is shown). %H A304383 Colin Barker, <a href="/A304383/b304383.txt">Table of n, a(n) for n = 1..1000</a> %H A304383 Ali Reza Ashrafi and Parisa Nikzad, <a href="http://www.chalcogen.ro/383_Ashrafi.pdf">Kekulé index and bounds of energy for nanostar dendrimers</a>, Digest J. of Nanomaterials and Biostructures, 4, No. 2, 2009, 383-388. %H A304383 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2). %F A304383 From _Colin Barker_, May 14 2018: (Start) %F A304383 G.f.: x*(67 - 62*x) / ((1 - x)*(1 - 2*x)). %F A304383 a(n) = 3*a(n-1) - 2*a(n-2) for n>2. %F A304383 (End) %p A304383 seq(36*2^n-5, n = 1 .. 40); %o A304383 (GAP) List([1..40],n->36*2^n-5); # _Muniru A Asiru_, May 13 2018 %o A304383 (PARI) Vec(x*(67 - 62*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ _Colin Barker_, May 14 2018 %Y A304383 Cf. A304382. %K A304383 nonn,easy %O A304383 1,1 %A A304383 _Emeric Deutsch_, May 13 2018