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 A279781 #15 Jul 07 2025 16:35:37 %S A279781 1,-3,4,-4,4,-3,-1,8,-16,24,-30,28,-12,-20,68,-128,184,-208,168,-32, %T A279781 -224,592,-1008,1344,-1408,960,224,-2240,4928,-7744,9664,-9216,4736, %U A279781 5120,-20608,39936,-58368,67840,-57600,16384,63488,-180224,315904,-431104,463872 %N A279781 Coefficients in the expansion of 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = 9/5. %C A279781 If n >= 23, then 32 divides a(n). %H A279781 Clark Kimberling, <a href="/A279781/b279781.txt">Table of n, a(n) for n = 0..1000</a> %H A279781 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (-2,-2,-2,-2). %F A279781 G.f.: 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = 9/5. %F A279781 G.f.: (1 - x) (1 - x^5)/(1 + 2 x + 2 x^2 + 2 x^3 + 2 x^4). %t A279781 z = 50; f[x_] := f[x] = Sum[Floor[(9/5)*(k + 1)] x^k, {k, 0, z}]; f[x] %t A279781 CoefficientList[Series[1/f[x], {x, 0, z}], x] %t A279781 LinearRecurrence[{-2,-2,-2,-2},{1,-3,4,-4,4,-3,-1},50] (* _Harvey P. Dale_, Jul 07 2025 *) %Y A279781 Cf. A279634, A279778, A279779, A279780. %K A279781 sign,easy %O A279781 0,2 %A A279781 _Clark Kimberling_, Dec 18 2016