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A091674 Numerator Q of probability P=Q(n)/365^(n-1) that two or more out of n people share the same birthday. 2
1, 1093, 795341, 481626601, 262130079485, 132974790903865, 64157156143943045, 29808728817823292065, 13447118719710220490765, 5923562823392985950002825, 2558600264156303883127171925, 1087010123072386037371040127025 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

A 365-day year and a uniform distribution of birthdays throughout the year is assumed.

LINKS

Table of n, a(n) for n=2..13.

P. Le Conte, Coincident Birthdays.

Mathforum at Drexel, The Birthday Problem. Ask Dr. Math: FAQ.

Eric Weisstein's World of Mathematics, Birthday Problem. Section in World of Mathematics.

FORMULA

Q(n)= (1-product_{i=1..n-1}(1-i/365))*365^(n-1).

MATHEMATICA

Q[n_] := (1 - Product[(1 - i/365), {i, 1, n - 1}])365^(n - 1); Table[ Q[n], {n, 2, 13}] (* Robert G. Wilson v, Feb 05 2004 *)

CROSSREFS

Cf. A014088, A091673 Probabilities for exactly two, A091715 Probabilities for three or more.

Sequence in context: A203858 A115192 A307220 * A022197 A259909 A124122

Adjacent sequences:  A091671 A091672 A091673 * A091675 A091676 A091677

KEYWORD

frac,nonn

AUTHOR

Hugo Pfoertner, Feb 03 2004

EXTENSIONS

More terms from Robert G. Wilson v, Feb 05 2004

Broken links corrected by Steven Finch, Jan 27 2009

STATUS

approved

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Last modified June 22 07:09 EDT 2021. Contains 345374 sequences. (Running on oeis4.)