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 A215144 #24 Apr 09 2023 03:57:25
%S A215144 1,20,39,58,77,96,115,134,153,172,191,210,229,248,267,286,305,324,343,
%T A215144 362,381,400,419,438,457,476,495,514,533,552,571,590,609,628,647,666,
%U A215144 685,704,723,742,761,780,799,818,837,856,875,894,913,932,951,970,989
%N A215144 a(n) = 19*n + 1.
%H A215144 Jeremy Gardiner, <a href="/A215144/b215144.txt">Table of n, a(n) for n = 0..999</a>
%H A215144 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A215144 From _G. C. Greubel_, Apr 19 2018: (Start)
%F A215144 a(n) = 2*a(n-1) - a(n-2).
%F A215144 G.f.: (1+18*x)/(1-x)^2.
%F A215144 E.g.f.: (1+19*x)*exp(x). (End)
%t A215144 Range[1, 1000, 19]
%t A215144 19*Range[0,60]+1 (* _Harvey P. Dale_, Nov 14 2014 *)
%t A215144 LinearRecurrence[{2,-1}, {1,20}, 50] (* _G. C. Greubel_, Apr 19 2018 *)
%o A215144 (PARI) for(n=0, 50, print1(19*n + 1, ", ")) \\ _G. C. Greubel_, Apr 19 2018
%o A215144 (Magma) I:=[1,20]; [n le 2 select I[n] else 2*Self(n-1) - Self(n-2): n in [1..30]]; // _G. C. Greubel_, Apr 19 2018
%Y A215144 Cf. A141868, A161705.
%Y A215144 First differences of A051873.
%K A215144 nonn,easy
%O A215144 0,2
%A A215144 _Jeremy Gardiner_, Aug 04 2012