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 A135493 #13 May 22 2025 08:27:30
%S A135493 1,2,4,8,16,32,62,122,240,472,928,1824,3586,7050,13860,27248,53568,
%T A135493 105312,207038,407026,800192,1573136,3092704,6080096,11953154,
%U A135493 23499282,46198372,90823608,178554512,351028928,690104702,1356710122,2667221872
%N A135493 Number of ways to toss a coin n times and not get a run of six.
%H A135493 G. C. Greubel, <a href="/A135493/b135493.txt">Table of n, a(n) for n = 0..1000</a>
%H A135493 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,1,1,1).
%F A135493 a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5).
%F A135493 From _R. J. Mathar_, Feb 10 2008: (Start)
%F A135493 O.g.f.: -1 - 2/(-1+x+x^2+x^3+x^4+x^5).
%F A135493 a(n) = 2*A001591(n+4) for n>=1. (End)
%t A135493 a[n_] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] + a[n - 4] + a[n - 5]; a[1] = 2; a[2] = 4; a[3] = 8; a[4] = 16; a[5] = 32; Array[a, 33] (* _Robert G. Wilson v_, Feb 10 2008 *)
%t A135493 LinearRecurrence[{1, 1, 1, 1, 1}, {2, 4, 8, 16, 32}, 25] (* _G. C. Greubel_, Oct 15 2016 *)
%Y A135493 Cf. A135491, A135492.
%K A135493 nonn
%O A135493 0,2
%A A135493 James R FitzSimons (cherry(AT)getnet.net), Feb 07 2008
%E A135493 More terms from _Robert G. Wilson v_, Feb 10 2008
%E A135493 a(0)=1 prepended by _Alois P. Heinz_, May 22 2025