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 A162539 #11 Sep 08 2022 08:45:46
%S A162539 1,6,21,55,120,231,405,660,1014,1484,2085,2829,3724,4773,5973,7315,
%T A162539 8784,10359,12013,13713,15420,17091,18681,20145,21440,22527,23373,
%U A162539 23952,24246,24246,23952,23373,22527,21440,20145,18681,17091,15420,13713
%N A162539 G.f. is the polynomial (1-x^3) * (1-x^6) * (1-x^9) * (1-x^12) * (1-x^15) * (1-x^18) / (1-x)^6.
%C A162539 This is a row of the triangle in A162499. Only finitely many terms are nonzero.
%H A162539 G. C. Greubel, <a href="/A162539/b162539.txt">Table of n, a(n) for n = 0..57</a>
%t A162539 CoefficientList[ Series[Times @@ (1 - x^(3 Range@6))/(1 - x)^6, {x, 0, 70}], x] (* _G. C. Greubel_, Jul 06 2018 and slightly modified by _Robert G. Wilson v_, Jul 23 2018 *)
%o A162539 (PARI) x='x+O('x^58); Vec((1-x^3)*(1-x^6)*(1-x^9)*(1-x^12)*(1-x^15)*(1-x^18)/(1-x)^6) /* complete row */ \\ _G. C. Greubel_, Jul 06 2018
%o A162539 (Magma) m:=58; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-x^3)*(1-x^6)*(1-x^9)*(1-x^12)*(1-x^15)*(1-x^18)/(1-x)^6)); /* complete row */ // _G. C. Greubel_, Jul 06 2018
%K A162539 nonn
%O A162539 0,2
%A A162539 _N. J. A. Sloane_, Dec 02 2009