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 A133343 #22 Jan 01 2024 11:44:42 %S A133343 1,1,15,43,281,1121,5895,26363,129361,601441,2884575,13587883, %T A133343 64675241,305992961,1452764055,6883436603,32652805921,154790287681, %U A133343 734067052335,3480407844523,16503687369401,78252676717601 %N A133343 a(n) = 2*a(n-1) + 13*a(n-2), for n>1, a(0)=1, a(1)=1. %C A133343 Binomial transform of A001023 (powers of 14), with interpolated zeros. %C A133343 a(n) is the number of compositions of n when there are 1 type of 1 and 14 types of other natural numbers. - _Milan Janjic_, Aug 13 2010 %H A133343 G. C. Greubel, <a href="/A133343/b133343.txt">Table of n, a(n) for n = 0..1000</a> %H A133343 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,13). %F A133343 G.f.: (1-x)/(1-2*x-13*x^2). %F A133343 a(n) = Sum_{k=0..n} A098158(n,k)*14^(n-k). - _Philippe Deléham_, Dec 26 2007 %F A133343 If p[1]=1, and p[i]=14, (i>1), and if A is Hessenberg matrix of order n defined by: A[i,j]=p[j-i+1], (i<=j), A[i,j]=-1, (i=j+1), and A[i,j]=0 otherwise. Then, for n>=1, a(n)=det A. - _Milan Janjic_, Apr 29 2010 %F A133343 a(n) = (b*i)^(n-1)*(b*i*ChebyshevU(n, -i/b) - ChebyshevU(n-1, -i/b)), with b = sqrt(13). - _G. C. Greubel_, Oct 15 2022 %t A133343 f[n_]:= Simplify[((1+Sqrt[14])^n + (1-Sqrt[14])^n)/2]; Array[f, 25, 0] (* Or *) %t A133343 CoefficientList[Series[(1+13x)/(1-2x-13x^2), {x, 0, 23}], x] (* Or *) %t A133343 LinearRecurrence[{2, 13}, {1, 1}, 25] (* Or *) %t A133343 Table[ MatrixPower[{{1, 2}, {7, 1}}, n][[1, 1]], {n, 0, 30}] (* _Robert G. Wilson v_, Sep 18 2013 *) %o A133343 (PARI) Vec((1-x)/(1-2*x-13*x^2)+O(x^99)) \\ _Charles R Greathouse IV_, Jan 12 2012 %o A133343 (Magma) [n le 2 select 1 else 2*Self(n-1) +13*Self(n-2): n in [1..41]]; // _G. C. Greubel_, Oct 15 2022 %o A133343 (SageMath) %o A133343 A133343=BinaryRecurrenceSequence(2,13,1,1) %o A133343 [A133343(n) for n in range(41)] # _G. C. Greubel_, Oct 15 2022 %Y A133343 Cf. A001023, A098158. %K A133343 nonn,easy %O A133343 0,3 %A A133343 _Philippe Deléham_, Dec 21 2007