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Number of ways to toss a coin n times and not get a run of six.
5

%I #8 Oct 15 2016 16:16:52

%S 2,4,8,16,32,62,122,240,472,928,1824,3586,7050,13860,27248,53568,

%T 105312,207038,407026,800192,1573136,3092704,6080096,11953154,

%U 23499282,46198372,90823608,178554512,351028928,690104702,1356710122,2667221872

%N Number of ways to toss a coin n times and not get a run of six.

%H G. C. Greubel, <a href="/A135493/b135493.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,1,1,1).

%F a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5).

%F From _R. J. Mathar_, Feb 10 2008: (Start)

%F O.g.f.: -2 - 2/(-1+x+x^2+x^3+x^4+x^5).

%F a(n) = 2*A001591(n+4). (End)

%t 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 LinearRecurrence[{1, 1, 1, 1, 1}, {2, 4, 8, 16, 32}, 25] (* _G. C. Greubel_, Oct 15 2016 *)

%Y Cf. A135491, A135492.

%K nonn

%O 1,1

%A James R FitzSimons (cherry(AT)getnet.net), Feb 07 2008

%E More terms from _Robert G. Wilson v_, Feb 10 2008