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 A047274 #46 Sep 01 2022 11:19:14
%S A047274 0,1,7,8,14,15,21,22,28,29,35,36,42,43,49,50,56,57,63,64,70,71,77,78,
%T A047274 84,85,91,92,98,99,105,106,112,113,119,120,126,127,133,134,140,141,
%U A047274 147,148,154,155,161,162,168,169
%N A047274 Numbers that are congruent to {0, 1} mod 7.
%C A047274 Nonnegative k such that k or 6*k + 1 is divisible by 7. - _Bruno Berselli_, Feb 13 2018
%H A047274 David Lovler, <a href="/A047274/b047274.txt">Table of n, a(n) for n = 1..1000</a>
%H A047274 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).
%F A047274 a(n) = 7*n - a(n-1) - 13 for n>1, a(1)=0. - _Vincenzo Librandi_, Aug 05 2010
%F A047274 From _R. J. Mathar_, Oct 08 2011: (Start)
%F A047274 a(n) = 7*n/2 - 19/4 - 5*(-1)^n/4.
%F A047274 G.f.: x^2*(1 + 6*x) / ((1 + x)*(x - 1)^2). (End)
%F A047274 a(n+1) = Sum_{k>=0} A030308(n,k)*A135092(k). - _Philippe Deléham_, Oct 17 2011
%F A047274 E.g.f.: 6 + ((14*x - 19)*exp(x) - 5*exp(-x))/4. - _David Lovler_, Aug 31 2022
%o A047274 (PARI) forstep(n=0,200,[1,6],print1(n", ")) \\ _Charles R Greathouse IV_, Oct 17 2011
%Y A047274 Cf. A030308, A135092.
%K A047274 nonn,easy
%O A047274 1,3
%A A047274 _N. J. A. Sloane_