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Search: id:A050231
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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). +0
8
0, 0, 1, 3, 8, 20, 47, 107, 238, 520, 1121, 2391, 5056, 10616, 22159, 46023, 95182, 196132, 402873, 825259, 1686408, 3438828, 6999071, 14221459, 28853662, 58462800, 118315137, 239186031, 483072832, 974791728, 1965486047 (list; graph; listen)
OFFSET

1,4

REFERENCES

Feller, W. An Introduction to Probability Theory and Its Application, Vol. 1, 2nd ed. New York: Wiley, p. 300, 1968.

LINKS

T. D. Noe, Table of n, a(n) for n=1..300

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Erich Friedman, Illustration of initial terms

FORMULA

a(n) = 2^n - Tribonacci(n+3), cf. A000073. - Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 23 2003

G.f.:x^3/((1-2x)(1-x-x^2-x^3)) [From Geoffrey Critzer (critzer.geoffrey(AT)usd443.org), Jan 29 2009]

CROSSREFS

Cf. A008466, A050232, A050233

Sequence in context: A138803 A048492 A006776 this_sequence A136305 A026712 A050232

Adjacent sequences: A050228 A050229 A050230 this_sequence A050232 A050233 A050234

KEYWORD

nonn,nice

AUTHOR

Eric Weisstein (eric(AT)weisstein.com)

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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