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 A301709 #21 Jul 31 2024 11:17:20
%S A301709 1,7,18,34,56,84,117,155,199,249,304,364,430,502,579,661,749,843,942,
%T A301709 1046,1156,1272,1393,1519,1651,1789,1932,2080,2234,2394,2559,2729,
%U A301709 2905,3087,3274,3466,3664,3868,4077,4291,4511,4737,4968,5204,5446,5694,5947,6205,6469,6739,7014,7294,7580,7872,8169,8471
%N A301709 Partial sums of A301708.
%C A301709 Linear recurrence and g.f. confirmed by Shutov/Maleev link in A301708. - _Ray Chandler_, Aug 30 2023
%H A301709 Ray Chandler, <a href="/A301709/b301709.txt">Table of n, a(n) for n = 0..1000</a>
%H A301709 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (3,-4,4,-3,1).
%F A301709 From _Colin Barker_, Apr 07 2018: (Start)
%F A301709 G.f.: (1 + 4*x + x^2 + 4*x^3 + x^4) / ((1 - x)^3*(1 + x^2)).
%F A301709 a(n) = ((-1/8+i/8)*((-5-5*i) + (-i)^n + i^(1+n)) + (11*n)/4 + (11*n^2)/4) where i=sqrt(-1).
%F A301709 a(n) = 3*a(n-1) - 4*a(n-2) + 4*a(n-3) - 3*a(n-4) + a(n-5) for n>4. (End)
%t A301709 LinearRecurrence[{3, -4, 4, -3, 1}, {1, 7, 18, 34, 56}, 100] (* _Paolo Xausa_, Jul 31 2024 *)
%Y A301709 Cf. A301708.
%K A301709 nonn
%O A301709 0,2
%A A301709 _N. J. A. Sloane_, Mar 26 2018
%E A301709 More terms from _R. J. Mathar_, Mar 30 2018