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 A046630 #32 Mar 07 2022 15:59:00
%S A046630 1,2,3,5,10,19,37,74,147,293,586,1171,2341,4682,9363,18725,37450,
%T A046630 74899,149797,299594,599187,1198373,2396746,4793491,9586981,19173962,
%U A046630 38347923,76695845,153391690,306783379,613566757,1227133514,2454267027
%N A046630 Number of cubic residues mod 2^n.
%H A046630 S. R. Finch and Pascal Sebah, <a href="https://arxiv.org/abs/math/0604465">Squares and Cubes Modulo n</a>, arXiv:math/0604465 [math.NT], 2006-2016.
%H A046630 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,1,-2).
%F A046630 a(n) = ceiling(2^(n+2)/7) [Finch-Sebah, page 12]. - _N. J. A. Sloane_, Sep 30 2018
%F A046630 G.f.: (-2*x^3-x^2+1)/((1-2*x)*(1-x^3)).
%F A046630 a(n) = A046530(2^n) = 2^(n+2)/7 + 2/3 - (5*A049347(n)+A049347(n-1))/21. - _R. J. Mathar_, Feb 27 2011
%F A046630 a(n) = 1 + A033138(n) for n >= 1. - _John Keith_, Mar 07 2022
%e A046630 For n=3, the cubes 0^3, 1^3, 2^3, ..., 7^3 reduced mod 2^3 = 8 are 0,1,0,3,0,5,0,7, five different values, so a(3)=5. - _N. J. A. Sloane_, Sep 30 2018
%p A046630 A049347 := proc(n) op( (n mod 3)+1,[1,-1,0]) ;end proc:
%p A046630 A046630 := proc(n) 2^(n+2)/7+2/3-(5*A049347(n)+A049347(n-1))/21 ; end proc: # _R. J. Mathar_, Feb 27 2011
%t A046630 LinearRecurrence[{2, 0, 1, -2}, {1, 2, 3, 5}, 33] (* _Jean-François Alcover_, Nov 17 2017 *)
%o A046630 (PARI) a(n)=(4<<n+6)\7 \\ _Charles R Greathouse IV_, Jan 03 2013
%Y A046630 Cf. A033138.
%K A046630 nonn,easy
%O A046630 0,2
%A A046630 _David W. Wilson_