What is the probability that the numbers that come up will be in ascending order (not necessarily strictly ascending, but never a lower number after a higher)?

Intended to be solved without a computer.

a(1)= 6 ;

a(2)=21 ;

a(3)=56 ;

> a(4)=126 ;

a(5)= 252 ;

......

a(n)=combin(n+5,n)

.......................

p(4)=126/(6^4)= 7/72

Edited on January 4, 2013, 6:56 pm

blackjack

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