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 A027055 #17 Sep 08 2022 08:44:49 %S A027055 1,18,59,146,319,652,1281,2456,4637,8670,16111,29822,55067,101528, %T A027055 187013,344276,633561,1165674,2144419,3944650,7255831,13346084, %U A027055 24547849,45151152,83046581,152747190,280946647,516742262,950438067 %N A027055 a(n) = T(n, n+4), T given by A027052. %H A027055 G. C. Greubel, <a href="/A027055/b027055.txt">Table of n, a(n) for n = 4..1003</a> %H A027055 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2,-1,2,-1). %F A027055 From _Colin Barker_, Feb 19 2016: (Start) %F A027055 a(n) = 4*a(n-1) -5*a(n-2) +2*a(n-3) -a(n-4) +2*a(n-5) -a(n-6) for n>9. %F A027055 G.f.: x^4*(1+14*x-8*x^2-2*x^3-5*x^4+4*x^5)/((1-x)^3*(1-x-x^2-x^3)). %F A027055 (End) %F A027055 a(n) = A001590(n+5) -n*(5+n), n>=4. - _R. J. Mathar_, Jun 15 2020 %p A027055 seq(coeff(series(x^4*(1+14*x-8*x^2-2*x^3-5*x^4+4*x^5)/((1-x)^3*(1-x-x^2-x^3)), x, n+1), x, n), n = 4..40); # _G. C. Greubel_, Nov 06 2019 %t A027055 LinearRecurrence[{4,-5,2,-1,2,-1}, {1,18,59,146,319,652}, 40] (* _G. C. Greubel_, Nov 06 2019 *) %o A027055 (PARI) my(x='x+O('x^40)); Vec(x^4*(1+14*x-8*x^2-2*x^3-5*x^4+4*x^5)/((1-x)^3*(1-x-x^2-x^3))) \\ _G. C. Greubel_, Nov 06 2019 %o A027055 (Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( x^4*(1+14*x-8*x^2-2*x^3-5*x^4+4*x^5)/((1-x)^3*(1-x-x^2-x^3)) )); // _G. C. Greubel_, Nov 06 2019 %o A027055 (Sage) %o A027055 def A027053_list(prec): %o A027055 P.<x> = PowerSeriesRing(ZZ, prec) %o A027055 return P(x^4*(1+14*x-8*x^2-2*x^3-5*x^4+4*x^5)/((1-x)^3*(1-x-x^2-x^3))).list() %o A027055 a=A027053_list(40); a[4:] # _G. C. Greubel_, Nov 06 2019 %o A027055 (GAP) a:=[1,18,59,146,319,652];; for n in [7..40] do a[n]:=4*a[n-1] -5*a[n-2]+2*a[n-3]-a[n-4]+2*a[n-5]-a[n-6]; od; a; # _G. C. Greubel_, Nov 06 2019 %K A027055 nonn,easy %O A027055 4,2 %A A027055 _Clark Kimberling_