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 A055853 #10 Sep 08 2022 08:45:01 %S A055853 0,1,8,43,190,743,2668,8989,28814,88720,264224,765088,2162624,5986304, %T A055853 16268800,43499264,114629120,298147840,766361600,1948794880, %U A055853 4907171840,12245598208,30305419264,74425892864,181481635840,439603953664 %N A055853 Convolution of A055852 with A011782. %C A055853 Eighth column of triangle A055587. %C A055853 T(n,6) of array T as in A049600. %H A055853 G. C. Greubel, <a href="/A055853/b055853.txt">Table of n, a(n) for n = 0..1000</a> %H A055853 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (14,-84,280,-560,672,-448,128). %F A055853 a(n) = T(n, 6)= A055587(n+6, 7). %F A055853 G.f.: x*(1-x)^6/(1-2*x)^7. %p A055853 seq(coeff(series(x*(1-x)^6/(1-2*x)^7, x, n+1), x, n), n = 0..30); # _G. C. Greubel_, Jan 16 2020 %t A055853 CoefficientList[Series[x*(1-x)^6/(1-2*x)^7, {x,0,30}], x] (* _G. C. Greubel_, Jan 16 2020 *) %o A055853 (PARI) my(x='x+O('x^30)); concat([0], Vec(x*(1-x)^6/(1-2*x)^7)) \\ _G. C. Greubel_, Jan 16 2020 %o A055853 (Magma) R<x>:=PowerSeriesRing(Integers(), 30); [0] cat Coefficients(R!( x*(1-x)^6/(1-2*x)^7 )); // _G. C. Greubel_, Jan 16 2020 %o A055853 (Sage) %o A055853 def A055853_list(prec): %o A055853 P.<x> = PowerSeriesRing(ZZ, prec) %o A055853 return P( x*(1-x)^6/(1-2*x)^7 ).list() %o A055853 A055853_list(30) # _G. C. Greubel_, Jan 16 2020 %Y A055853 Cf. A011782, A049600, A055587, A055852. %K A055853 nonn,easy %O A055853 0,3 %A A055853 _Wolfdieter Lang_ May 30 2000