

A085813


Number of cards that need to be drawn (with replacement) from a deck of n cards to have a 95% or greater chance of seeing each card at least once.


1



1, 6, 11, 16, 21, 27, 33, 38, 44, 51, 57, 63, 70, 76, 83, 90, 96, 103, 110, 117, 124, 131, 138, 145, 152, 159, 167, 174, 181, 189, 196, 203, 211, 218, 226, 233, 241, 248, 256, 264, 271, 279, 287, 294, 302, 310, 318, 326, 333, 341, 349, 357, 365, 373, 381, 389
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

The probability that there are at most k different cards in t drawings is (k/m)^t * binomial(m,k). This also includes the cases with k1 different cards, which we want to subtract. Inclusion and exclusion leads to the formula Sum_{k=1..m} (1)^(mk) * (k/m)^t * binomial(m,k).


LINKS

Table of n, a(n) for n=1..56.


EXAMPLE

a(2)=6 because you have to throw a coin 6 times to get both sides at least once with probability greater than or equal to 0.95. (The probability of getting only one side in a series of 6 throws is (1/2)^6 * 2 = 1/32 = 0.03125 < 0.05.)
a(6)=27 because you have to roll a die 27 times to see all 6 possible outcomes with a probability over 0.95. (If you roll a die 27 times, the probability of getting all 6 sides at least once is 0.95658638... . If you roll the die only 26 times, the probability is 0.94798274... .)


MATHEMATICA

f[1] = 1; f[n_] := f[n] = Block[{k = f[n  1]}, While[ 2StirlingS2[k, n]*n!/n^k < 19/10, k++ ]; k]; Table[ f[n], {n, 1, 56}]


CROSSREFS

Cf. A073593 (number of drawings for a 50% probability of seeing each card, = median) and A060293 (expected value of the number of drawings until each card is drawn once).
Cf. A090582.
Sequence in context: A315475 A315476 A315477 * A315478 A315479 A315480
Adjacent sequences: A085810 A085811 A085812 * A085814 A085815 A085816


KEYWORD

nonn


AUTHOR

Alfred Heiligenbrunner, Jul 25 2003


EXTENSIONS

More terms from Robert G. Wilson v, Sep 07 2003


STATUS

approved



