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 A162667 #11 Sep 08 2022 08:45:46 %S A162667 1,10,103,1090,11809,130450,1463527,16616890,190375681,2195675290, %T A162667 25447064743,295960791730,3450850554529,40308814292770, %U A162667 471443782066087,5518920654923050,64648366238050561,757632021233475370 %N A162667 a(n) = 20*a(n-1) - 97*a(n-2) for n > 1; a(0) = 1, a(1) = 10. %C A162667 Binomial transform of A152056. Tenth binomial transform of powers of 3 interleaved with zeros. %H A162667 G. C. Greubel, <a href="/A162667/b162667.txt">Table of n, a(n) for n = 0..930</a> %H A162667 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (20,-97). %F A162667 a(n) = ((10+sqrt(3))^n + (10-sqrt(3))^n)/2. %F A162667 G.f.: (1-10*x)/(1-20*x+97*x^2). %p A162667 seq(coeff(series((1-10*x)/(1-20*x+97*x^2), x, n+1), x, n), n = 0..20); # _G. C. Greubel_, Aug 27 2019 %t A162667 LinearRecurrence[{20,-97}, {1,10}, 20] (* _G. C. Greubel_, Aug 27 2019 *) %o A162667 (Magma) [ n le 2 select 9*n-8 else 20*Self(n-1)-97*Self(n-2): n in [1..18] ]; %o A162667 (PARI) my(x='x+O('x^20)); Vec((1-10*x)/(1-20*x+97*x^2)) \\ _G. C. Greubel_, Aug 27 2019 %o A162667 (Sage) %o A162667 def A162667_list(prec): %o A162667 P.<x> = PowerSeriesRing(ZZ, prec) %o A162667 return P((1-10*x)/(1-20*x+97*x^2)).list() %o A162667 A162667_list(20) # _G. C. Greubel_, Aug 27 2019 %o A162667 (GAP) a:=[1,10];; for n in [3..20] do a[n]:=20*a[n-1]-97*a[n-2]; od; a; # _G. C. Greubel_, Aug 27 2019 %Y A162667 Cf. A152056, A000244 (powers of 3). %K A162667 nonn,easy %O A162667 0,2 %A A162667 _Klaus Brockhaus_, Jul 15 2009