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 A296909 #20 Feb 12 2018 11:19:43 %S A296909 1,4,12,24,39,59,84,112,143,179,220,264,311,363,420,480,543,611,684, %T A296909 760,839,923,1012,1104,1199,1299,1404,1512,1623,1739,1860,1984,2111, %U A296909 2243,2380,2520,2663,2811,2964,3120,3279,3443,3612,3784,3959,4139,4324,4512 %N A296909 Partial sums of A296368. %H A296909 Rémy Sigrist, <a href="/A296909/b296909.txt">Table of n, a(n) for n = 0..1000</a> %H A296909 Reticular Chemistry Structure Resource (RCSR), <a href="http://rcsr.net/layers/mcm">The mcm tiling (or net)</a> %H A296909 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (3,-4,4,-3,1). %F A296909 From _Colin Barker_, Dec 23 2017: (Start) %F A296909 G.f.: (1 + x + 4*x^2 + 2*x^4 + x^5 - x^6) / ((1 - x)^3*(1 + x^2)). %F A296909 a(n) = (-1/4-i/4)*((1-i) + (-i)^n - i*i^n) + 2*n + 2*n^2 for n>1, where i=sqrt(-1). %F A296909 a(n) = 3*a(n-1) - 4*a(n-2) + 4*a(n-3) - 3*a(n-4) + a(n-5) for n>6. %F A296909 (End) %o A296909 (PARI) Vec((1 + x + 4*x^2 + 2*x^4 + x^5 - x^6) / ((1 - x)^3*(1 + x^2)) + O(x^50)) \\ _Colin Barker_, Dec 24 2017 %Y A296909 Cf. A296368. %K A296909 nonn,easy %O A296909 0,2 %A A296909 _N. J. A. Sloane_, Dec 22 2017 %E A296909 Terms a(8)-a(20) and RCSR link from _Davide M. Proserpio_, Dec 22 2017 %E A296909 More terms from _Rémy Sigrist_, Dec 23 2017