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 A228321 #9 Jul 04 2023 11:33:22 %S A228321 15,33,62,103,156,221,298,387,488,601,726,863,1012,1173,1346,1531, %T A228321 1728,1937,2158,2391,2636,2893,3162,3443,3736,4041,4358,4687,5028, %U A228321 5381,5746,6123,6512,6913,7326,7751,8188,8637,9098,9571,10056,10553,11062 %N A228321 The Wiener index of the graph obtained by applying Mycielski's construction to the path graph on n vertices (n>=2). %D A228321 D. B. West, Introduction to Graph Theory, 2nd ed., Prentice-Hall, NJ, 2001, p. 205. %H A228321 R. Balakrishnan, S. F. Raj, <a href="http://dx.doi.org/10.7151/dmgt.1509">The Wiener number of powers of the Mycielskian</a>, Discussiones Math. Graph Theory, 30, 2010, 489-498 (see Theorem 2.1). %H A228321 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3, -3, 1). %F A228321 a(2)=15; a(n) = 6n^2 - 13n + 18 (n>=3). %F A228321 G.f.: x^2*(15-12*x+8*x^2+x^3)/(1-x)^3. %e A228321 a(2)=15 because the Mycielskian of the 1-edge graph is the cycle graph C(5) with Wiener index 5*1+5*2 = 15. %p A228321 a := proc (n) if n = 2 then 15 else 6*n^2-13*n+18 end if end proc: seq(a(n), n = 2 .. 45); %K A228321 nonn,easy %O A228321 2,1 %A A228321 _Emeric Deutsch_, Aug 27 2013