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 A317983 #8 Aug 18 2018 11:24:25 %S A317983 420,7140,41160,148680,411180,955500,1963920,3684240,6439860,10639860, %T A317983 16789080,25498200,37493820,53628540,74891040,102416160,137494980, %U A317983 181584900,236319720,303519720,385201740,483589260,601122480,740468400,904530900,1096460820 %N A317983 Expansion of 420*x*(1 + x)*(1 + 10*x + x^2) / (1 - x)^6. %C A317983 Seems to be the negative of the third column of A316387. %H A317983 Colin Barker, <a href="/A317983/b317983.txt">Table of n, a(n) for n = 1..1000</a> %H A317983 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,20,-15,6,-1). %F A317983 G.f.: 420*x*(1 + x)*(1 + 10*x + x^2) / (1 - x)^6. %F A317983 a(n) = 420 * A000538(n). %F A317983 a(n) = 84*n^5 + 210*n^4 + 140*n^3 - 14*n. %F A317983 a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6. %o A317983 (PARI) Vec(420*x*(1 + x)*(1 + 10*x + x^2) / (1 - x)^6 + O(x^40)) %o A317983 (PARI) a(n) = 84*n^5 + 210*n^4 + 140*n^3 - 14*n %Y A317983 Cf. A000538, A316387, A317981, A317982, A317984. %K A317983 nonn,easy %O A317983 1,1 %A A317983 _Colin Barker_, Aug 13 2018