%I A050231
%S A050231 0,0,1,3,8,20,47,107,238,520,1121,2391,5056,10616,22159,46023,95182,
%T A050231 196132,402873,825259,1686408,3438828,6999071,14221459,28853662,
%U A050231 58462800,118315137,239186031,483072832,974791728,1965486047
%N A050231 a(n) is the number of n-tosses having a run of 3 or more heads for a 
               fair coin (i.e. probability is a(n)/2^n).
%D A050231 Feller, W. An Introduction to Probability Theory and Its Application, 
               Vol. 1, 2nd ed. New York: Wiley, p. 300, 1968.
%H A050231 T. D. Noe, <a href="b050231.txt">Table of n, a(n) for n=1..300</a>
%H A050231 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               Run.html">Link to a section of The World of Mathematics.</a>
%H A050231 Erich Friedman, <a href="a050231.gif">Illustration of initial terms</
               a>
%F A050231 a(n) = 2^n - Tribonacci(n+3), cf. A000073. - Vladeta Jovovic (vladeta(AT)eunet.rs), 
               Feb 23 2003
%F A050231 G.f.:x^3/((1-2x)(1-x-x^2-x^3)) [From Geoffrey Critzer (critzer.geoffrey(AT)usd443.org), 
               Jan 29 2009]
%Y A050231 Cf. A008466, A050232, A050233
%Y A050231 Sequence in context: A138803 A048492 A006776 this_sequence A136305 A026712 
               A050232
%Y A050231 Adjacent sequences: A050228 A050229 A050230 this_sequence A050232 A050233 
               A050234
%K A050231 nonn,nice
%O A050231 1,4
%A A050231 Eric Weisstein (eric(AT)weisstein.com)