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 A142584 #12 Apr 14 2021 22:26:30
%S A142584 2,4,6,10,18,28,46,76,122,198,322,520,842,1364,2206,3570,5778,9348,
%T A142584 15126,24476,39602,64078,103682,167760,271442,439204,710646,1149850,
%U A142584 1860498,3010348,4870846,7881196,12752042,20633238,33385282,54018520,87403802,141422324,228826126
%N A142584 a(n) = A014217(n+1) - A115360(n+2).
%H A142584 G. C. Greubel, <a href="/A142584/b142584.txt">Table of n, a(n) for n = 1..1000</a>
%F A142584 a(n) = Lucas(n+1) - (1/2)*(1 + (-1)^((n+2) mod 3)). - _G. C. Greubel_, Apr 14 2021
%t A142584 Table[LucasL[n+1] - (1/2)*(1+(-1)^Mod[n+2, 3]), {n, 45}] (* _G. C. Greubel_, Apr 14 2021 *)
%o A142584 (Magma) [Lucas(n+1) - (1/2)*(1 + (-1)^((n+2) mod 3)): n in [1..45]]; // _G. C. Greubel_, Apr 14 2021
%o A142584 (Sage) [lucas_number2(n+1,1,-1) - (1/2)*(1 + (-1)^((n+2)%3)) for n in (1..45)] # _G. C. Greubel_, Apr 14 2021
%Y A142584 Cf. A000032, A014217, A115360.
%K A142584 nonn
%O A142584 1,1
%A A142584 _Paul Curtz_, Sep 21 2008
%E A142584 Edited by _Omar E. Pol_ and _N. J. A. Sloane_, Jan 06 2009
%E A142584 More terms from _Daniel Suteu_, Nov 24 2019