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 A037618 #11 Aug 23 2025 17:03:49
%S A037618 2,8,35,142,568,2275,9102,36408,145635,582542,2330168,9320675,
%T A037618 37282702,149130808,596523235,2386092942,9544371768,38177487075,
%U A037618 152709948302,610839793208,2443359172835,9773436691342,39093746765368
%N A037618 Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,0,3.
%H A037618 <a href="/index/Ar#2-automatic">Index entries for 2-automatic sequences</a>.
%H A037618 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,0,1,-4)
%F A037618 G.f.: x*(2+3*x^2) / ( (x-1)*(4*x-1)*(1+x+x^2) ). - _R. J. Mathar_, Apr 27 2015
%F A037618 A007090(a(n)) = A037624(n). - _R. J. Mathar_, Apr 27 2015
%t A037618 Table[FromDigits[PadRight[{},n,{2,0,3}],4],{n,30}] (* or *) LinearRecurrence[{4,0,1,-4},{2,8,35,142},30] (* _Harvey P. Dale_, Aug 23 2025 *)
%o A037618 (PARI) a(n)=([0,1,0,0; 0,0,1,0; 0,0,0,1; -4,1,0,4]^(n-1)*[2;8;35;142])[1,1] \\ _Charles R Greathouse IV_, Feb 13 2017
%K A037618 nonn,base,easy,changed
%O A037618 1,1
%A A037618 _Clark Kimberling_