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 A221862 #23 Apr 02 2024 11:39:30 %S A221862 1,5,21,83,319,1208,4535,16932,62986,233702,865513,3201026,11826582, %T A221862 43660921,161090910,594092895,2190225106,8072519511,29746921227, %U A221862 109599320930,403758993204,1487294628182,5478244777582,20177275278559,74313150143975,273687550281967 %N A221862 Expansion of (1-3*x+x^2)*(1-x)/(1-9*x+28*x^2-35*x^3+15*x^4-x^5). %C A221862 A diagonal of the square array A223968. %H A221862 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (9,-28,35,-15,1). %F A221862 a(n) = A223968(n,n+3). %F A221862 G.f.: (1-3*x+x^2)*(1-x)/(1-9*x+28*x^2-35*x^3+15*x^4-x^5). %F A221862 a(n) = 9*a(n-1) - 28*a(n-2) + 35*a(n-3) - 15*a(n-4) + a(n-5) with a(0) = 1, a(1) = 5, a(2) = 21, a(3) = 83, a(4) = 319. %Y A221862 Cf. A223968 %K A221862 nonn,easy %O A221862 0,2 %A A221862 _Philippe Deléham_, Apr 10 2013