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 #15
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Your logic is excellent, Melody.

This helps to explain the formula referenced here.

http://web2.0calc.com/questions/this-is-a-continuation-of-an-earlier-counting-question-that-nauseated-and-geno-answered

 

N1i=0(1)i(Ni)(Ni)kCurrent problem10i=0(1)i(Ni)(Ni)11=129230640

 

This formula is a modification of the formula to generate Stirling numbers of the second kind.

 

Sterling number -2nd type: 1N!N1i=0(1)i(Ni)(Ni)k

 

The modification is to multiply by N!.

 

Wolfram input   

StirlingS2[11, 6] = 179487

Multiplying by 6! Returns value above.

StirlingS2[11, 6]*6! = 129320640

 

Stirling numbers of the second kind generate solutions to bąll and box distributions where the bąlls are unique and the boxes are identical. 

 

This die rolling problem is equivalent to a bąll (die roll) and box (die face) problem where both the bąlls and boxes are unique, requiring an increase in the counts of solutions by a factor of 6!

 

General form:

 

11!(B1!)(B2!)(B3!)(B4!)(B5!)(B6!)=unique distributionswhere B1+B2+B3+B4+B5+B6=11 with Bi0

 

 Expanded this by using a generating function for polynomials

 

[g^y - 1]^6 (The minus 1 correlates to having no empty box).

 

The general polynomial expansion is

 

g(6y)(61)g(5y)+(62)g(4y)(63)g(3y)+(64)g(2y)(65)g(y)+1

 

 

Now in terms of  y11 for the 11 rolls of the die.

 

(61111!)+6(51111!)+15(41111!)+20(31111!)+15(21111!)+6(11111!)

 

 

Factor out the (111!)(111!)[(6116(511)+15(411)20(311)+15(211)6(111)]=(111!)(129230640)

 

Note the similarity to the modification of the sterling number formula, where (6!) is factored out.

 

129230640116=0.0.3562064186099 (Probability of rolling at least one of each number (1-6) for 11 rolls of a fair die)

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A Markov matrix may also be used to solve this type of problem.   

Mar 2, 2016