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 A077169 #16 Dec 13 2022 02:14:15
%S A077169 1,2,4,7,11,15,20,26,33,41,50,60,71,83,96,110,125,141,158,176,195,215,
%T A077169 236,258,281,305,330,356,383,411,440,470,501,533,566,600,635,671,708,
%U A077169 746,785,825,866,908,951,995,1040,1086,1133,1181,1230,1280,1331,1383
%N A077169 Initial terms of rows of A077168.
%H A077169 G. C. Greubel, <a href="/A077169/b077169.txt">Table of n, a(n) for n = 0..5000</a>
%H A077169 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A077169 For n>3, a(n) = (n^2-n+10)/2.
%F A077169 From _G. C. Greubel_, Jul 13 2017: (Start)
%F A077169 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3), n >= 7.
%F A077169 G.f.: (1-x+x^2-x^5 + x^6)/(1-x)^3.
%F A077169 E.g.f.: (1/2)*(x^2 + 10)*exp(x) - 4 - 3*x + x^2 - x^3/6. (End)
%F A077169 Sum_{n>=0} 1/a(n) = 1177/840 + 2*Pi*tanh(sqrt(39)*Pi/2)/sqrt(39). - _Amiram Eldar_, Dec 13 2022
%t A077169 Join[{1, 2, 4, 7}, Table[(n^2 - n + 10)/2, {n, 4, 50}]] (* _G. C. Greubel_, Jul 13 2017 *)
%o A077169 (PARI) concat([1,2,4,7], for(n=4,50, print1((n^2 - n +10)/2, ", "))) \\ _G. C. Greubel_, Jul 13 2017
%Y A077169 Cf. A077168, A077170.
%K A077169 nonn,easy
%O A077169 0,2
%A A077169 _Amarnath Murthy_, Nov 01 2002
%E A077169 More terms from _Sascha Kurz_, Feb 10 2003