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 A145976 #47 Feb 28 2024 16:00:25
%S A145976 1,1,-6,-13,29,120,-83,-923,-342,6119,8513,-34320,-93911,146329,
%T A145976 803706,-220597,-5846539,-4302360,36623413,66739933,-189623958,
%U A145976 -656803489,670564217,5268188640,574239121,-36303081359,-40322755206,213798814307
%N A145976 Expansion of 1/(1-x*(1-7*x)).
%C A145976 Row sums of Riordan array (1,x(1-7x)).
%H A145976 G. C. Greubel, <a href="/A145976/b145976.txt">Table of n, a(n) for n = 0..1500</a>
%H A145976 Taras Goy and Mark Shattuck, <a href="https://doi.org/10.2478/amsil-2023-0027">Determinants of Toeplitz-Hessenberg Matrices with Generalized Leonardo Number Entries</a>, Ann. Math. Silesianae (2023). See p. 17.
%H A145976 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,-7).
%F A145976 a(n) = a(n-1) - 7*a(n-2), a(0)=1, a(1)=1.
%F A145976 a(n) = Sum_{k=0..n} A109466(n,k)*7^(n-k).
%t A145976 Join[{a=1,b=1},Table[c=b-7*a;a=b;b=c,{n,80}]] (* _Vladimir Joseph Stephan Orlovsky_, Jan 22 2011 *)
%t A145976 CoefficientList[Series[1/(1-x(1-7x)),{x,0,50}],x] (* or *) LinearRecurrence[{1,-7},{1,1},50] (* _Harvey P. Dale_, May 11 2011 *)
%o A145976 (Sage) [lucas_number1(n,1,7) for n in range(1, 29)] # _Zerinvary Lajos_, Apr 22 2009
%o A145976 (PARI) Vec(1/(1-x*(1-7*x)) + O(x^40)) \\ _Michel Marcus_, Jan 29 2016
%o A145976 (Magma) I:=[1,1]; [n le 2 select I[n] else Self(n-1) - 7*Self(n-2): n in [1..30]]; // _G. C. Greubel_, Jan 19 2018
%Y A145976 Cf. A010892, A107920, A106852, A106853, A106854, A145934.
%K A145976 sign,easy
%O A145976 0,3
%A A145976 _Philippe Deléham_, Oct 26 2008
%E A145976 Corrected by _Zerinvary Lajos_, Apr 22 2009
%E A145976 Corrected by _D. S. McNeil_, Aug 20 2010