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 A011901 #33 Feb 01 2025 19:54:37
%S A011901 0,0,0,0,1,3,6,11,17,26,37,52,69,90,114,143,176,214,257,306,360,420,
%T A011901 486,559,639,726,821,923,1034,1153,1282,1419,1566,1722,1889,2066,2254,
%U A011901 2453,2664,2886,3120,3366,3625,3897,4182,4481,4793,5120,5461,5818,6189,6576,6978,7397,7832,8284,8753,9240,9744,10266,10806,11365,11943,12540,13157,13793,14450,15127
%N A011901 a(n) = floor( n*(n-1)*(n-2)/19 ).
%H A011901 G. C. Greubel, <a href="/A011901/b011901.txt">Table of n, a(n) for n = 0..2000</a>
%H A011901 <a href="/index/Rec#order_22">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-3,3,-1).
%F A011901 a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-19) -3*a(n-20) +3*a(n-21) -a(n-22). - _R. J. Mathar_, Apr 15 2010
%F A011901 G.f.: x^4 (1+x^4) (1+x^3 (1-x+x^3+x^6) (1+(-1+x) x (1+x^2)))/(1+x (-3+x (3+x (-1+(-1+x)^3 x^16)))). - _Peter J. C. Moses_, Jun 02 2014
%F A011901 G.f.: x^4*(1+x^4)*(1+x^3-2*x^4+2*x^5-x^6+x^7+x^11-x^12+x^13)/((1-x)^3*(1-x^19)). - _G. C. Greubel_, Oct 17 2024
%t A011901 Table[Floor[n(n-1)(n-2)/19],{n,0,75}] (* or *)
%t A011901 LinearRecurrence[{3,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-3,3,-1}, {0,0,0,0, 1,3,6,11,17,26,37,52,69,90,114,143,176,214,257,306,360,420}, 76] (* _Harvey P. Dale_, May 30 2021 *)
%o A011901 (PARI) a(n)=n*(n-1)*(n-2)\19 \\ _Charles R Greathouse IV_, Oct 21 2022
%o A011901 (Magma) [Floor(6*Binomial(n,3)/19): n in [0..75]]; // _G. C. Greubel_, Oct 17 2024
%o A011901 (Python) print([6*binomial(n,3)//19 for n in range(76)]) # _G. C. Greubel_, Oct 17 2024
%Y A011901 Cf. A011886.
%K A011901 nonn,easy
%O A011901 0,6
%A A011901 _N. J. A. Sloane_
%E A011901 More terms added by _G. C. Greubel_, Oct 18 2024