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 A298375 #31 Jan 20 2018 09:11:19
%S A298375 2,5,11,18,29,43,61,84,111,145,183,230,281,343,409,488,571,669,771,
%T A298375 890,1013,1155,1301,1468,1639,1833,2031,2254,2481,2735,2993,3280,3571,
%U A298375 3893,4219,4578,4941,5339,5741,6180,6623,7105,7591,8118,8649,9223,9801,10424
%N A298375 Partial sums of A230584.
%H A298375 Colin Barker, <a href="/A298375/b298375.txt">Table of n, a(n) for n = 1..1000</a>
%H A298375 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (2,1,-4,1,2,-1).
%F A298375 Let g = n + ((n + 1) mod 2), then for n > 1,
%F A298375 a(n) = (g^3 + 6*g^2 + 11*g + 18) / 12 - If(n mod 2 = 1, 0, ((n + 2) / 2)^2 + 2).
%F A298375 From _Colin Barker_, Jan 18 2018: (Start)
%F A298375 G.f.: x*(2 + x - x^2 - x^3 + 2*x^5 - x^6) / ((1 - x)^4*(1 + x)^2).
%F A298375 a(n) = (n^3 + 6*n^2 + 14*n) / 12 for n>1 and even.
%F A298375 a(n) = (n^3 + 6*n^2 + 11*n + 18) / 12 for n>1 and odd.
%F A298375 a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + a(n-4) + 2*a(n-5) - a(n-6) for n>6.
%F A298375 (End)
%e A298375 For n = 5 then a(5) = 2+3+6+7+11 = 29.
%t A298375 CoefficientList[ Series[(2 + x - x^2 - x^3 + 2x^5 - x^6)/((x -1)^4 (x + 1)^2), {x, 0, 50}], x] (* _Robert G. Wilson v_, Jan 18 2018 *)
%o A298375 (PARI) Vec(x*(2 + x - x^2 - x^3 + 2*x^5 - x^6) / ((1 - x)^4*(1 + x)^2) + O(x^50)) \\ _Colin Barker_, Jan 18 2018
%Y A298375 Cf. A230584.
%K A298375 nonn,easy
%O A298375 1,1
%A A298375 _Gerald Hillier_, Jan 18 2018