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 A047353 #28 Sep 11 2022 22:17:59
%S A047353 1,2,8,9,15,16,22,23,29,30,36,37,43,44,50,51,57,58,64,65,71,72,78,79,
%T A047353 85,86,92,93,99,100,106,107,113,114,120,121,127,128,134,135,141,142,
%U A047353 148,149,155,156,162,163,169,170
%N A047353 Numbers that are congruent to {1, 2} mod 7.
%H A047353 David Lovler, <a href="/A047353/b047353.txt">Table of n, a(n) for n = 1..1000</a>
%H A047353 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A047353 From _R. J. Mathar_, Oct 08 2011: (Start)
%F A047353 a(n) = 7*n/2 - 15/4 - 5*(-1)^n/4.
%F A047353 G.f.: x*(1 + x + 5*x^2) / ( (1+x)*(x-1)^2 ). (End)
%F A047353 E.g.f.: 5 + ((14*x -15)*exp(x) - 5*exp(-x))/4. - _David Lovler_, Sep 11 2022
%t A047353 LinearRecurrence[{1,1,-1},{1,2,8},50] (* _Harvey P. Dale_, Nov 29 2014 *)
%o A047353 (PARI) a(n) = (14*n - 15 - 5*(-1)^n)/4 \\ _David Lovler_, Sep 11 2022
%K A047353 nonn,easy
%O A047353 1,2
%A A047353 _N. J. A. Sloane_