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 A017245 #58 Dec 08 2024 10:21:16
%S A017245 7,16,25,34,43,52,61,70,79,88,97,106,115,124,133,142,151,160,169,178,
%T A017245 187,196,205,214,223,232,241,250,259,268,277,286,295,304,313,322,331,
%U A017245 340,349,358,367,376,385,394,403,412,421,430,439,448,457,466,475,484
%N A017245 a(n) = 9*n + 7.
%C A017245 Numbers whose digital root is 7. - _Halfdan Skjerning_, Mar 15 2018
%H A017245 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A017245 J. Laroche and N. J. A. Sloane, <a href="/A004207/a004207.pdf">Correspondence, 1977</a>
%H A017245 Leo Tavares, <a href="/A017245/a017245.jpg">Illustration: Triple Triangular Frames</a>
%H A017245 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A017245 a(n)^2 = A156676(n+1) + A017137(n). - _Reinhard Zumkeller_, Jul 13 2010
%F A017245 From _Vincenzo Librandi_, Apr 30 2015: (Start)
%F A017245 G.f.: (7+2*x)/(1-x)^2.
%F A017245 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>2. (End)
%F A017245 E.g.f.: exp(x)*(7 + 9*x). - _Stefano Spezia_, Dec 08 2024
%t A017245 Range[7, 1000, 9] (* _Vladimir Joseph Stephan Orlovsky_, May 28 2011 *)
%t A017245 Table[9 n + 7, {n, 0, 70}] (* or *) CoefficientList[Series[(7 + 2 x)/(1 - x)^2, {x, 0, 60}], x] (* _Vincenzo Librandi_, Apr 30 2015 *)
%t A017245 LinearRecurrence[{2,-1},{7,16},60] (* _Harvey P. Dale_, Jul 30 2024 *)
%o A017245 (Magma) [9*n+7: n in [0..60]]; // _Vincenzo Librandi_, Apr 30 2015
%o A017245 (PARI) vector(100,n,9*n-2) \\ _Derek Orr_, Apr 30 2015
%Y A017245 Cf. A008591, A017233.
%K A017245 nonn,easy
%O A017245 0,1
%A A017245 _N. J. A. Sloane_