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 A081686 #16 Sep 12 2024 19:33:17 %S A081686 1,1,-1,19,467,5611,53459,455659,3648707,28119691,211372019, %T A081686 1562038699,11405181347,82545287371,593501306579,4245828252139, %U A081686 30255066944387,214924122640651,1522971386761139,10770190567911979,76039651374633827,536127709619251531,3775797660906839699,26567026101757594219 %N A081686 a(n) = 7^n - 6^n - 5^n - 4^n + 3*3^n. %C A081686 Binomial transform of A081685. %H A081686 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (25,-245,1175,-2754,2520). %F A081686 G.f.: -(1326*x^4-886*x^3+219*x^2-24*x+1)/((3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)). [_Colin Barker_, Sep 07 2012] %F A081686 From _Elmo R. Oliveira_, Sep 12 2024: (Start) %F A081686 E.g.f.: exp(3*x)*(exp(4*x) - exp(3*x) - exp(2*x) - exp(x) + 3). %F A081686 a(n) = 25*a(n-1) - 245*a(n-2) + 1175*a(n-3) - 2754*a(n-4) + 2520*a(n-5) for n > 4. (End) %Y A081686 Cf. A081685, A081687. %K A081686 easy,sign %O A081686 0,4 %A A081686 _Paul Barry_, Mar 30 2003 %E A081686 a(22)-a(23) from _Elmo R. Oliveira_, Sep 12 2024