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 A055854 #12 Nov 04 2023 05:24:26
%S A055854 0,1,9,53,253,1059,4043,14407,48639,157184,489872,1480608,4358752,
%T A055854 12541184,35364864,97960192,267050240,717619200,1903452160,4989337600,
%U A055854 12937052160,33212530688,84484882432,213090238464,533236219904
%N A055854 Convolution of A055853 with A011782.
%C A055854 Ninth column of triangle A055587.
%C A055854 T(n,7) of array T as in A049600.
%H A055854 G. C. Greubel, <a href="/A055854/b055854.txt">Table of n, a(n) for n = 0..1000</a>
%H A055854 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (16,-112,448,-1120,1792,-1792,1024,-256).
%F A055854 a(n)= T(n, 7)= A055587(n+7, 8).
%F A055854 G.f.: x*(1-x)^7/(1-2*x)^8.
%p A055854 seq(coeff(series(x*(1-x)^7/(1-2*x)^8, x, n+1), x, n), n = 0..30); # _G. C. Greubel_, Jan 16 2020
%t A055854 CoefficientList[Series[x*(1-x)^7/(1-2*x)^8, {x,0,30}], x] (* _G. C. Greubel_, Jan 16 2020 *)
%t A055854 LinearRecurrence[{16,-112,448,-1120,1792,-1792,1024,-256},{0,1,9,53,253,1059,4043,14407,48639,157184},40] (* _Harvey P. Dale_, Nov 04 2023 *)
%o A055854 (PARI) my(x='x+O('x^30)); concat([0], Vec(x*(1-x)^7/(1-2*x)^8)) \\ _G. C. Greubel_, Jan 16 2020
%o A055854 (Magma) R<x>:=PowerSeriesRing(Integers(), 30); [0] cat Coefficients(R!( x*(1-x)^7/(1-2*x)^8 )); // _G. C. Greubel_, Jan 16 2020
%o A055854 (Sage)
%o A055854 def A055854_list(prec):
%o A055854 P.<x> = PowerSeriesRing(ZZ, prec)
%o A055854 return P( x*(1-x)^7/(1-2*x)^8 ).list()
%o A055854 A055854_list(30) # _G. C. Greubel_, Jan 16 2020
%Y A055854 Cf. A011782, A049600, A055587, A055853.
%K A055854 nonn,easy
%O A055854 0,3
%A A055854 _Wolfdieter Lang_ May 30 2000