login
The number of times a point sum n is attained in all 7^6 permutations of throwing 7 dice.
2

%I #7 Jan 30 2016 16:36:10

%S 1,7,28,84,210,462,917,1667,2807,4417,6538,9142,12117,15267,18327,

%T 20993,22967,24017,24017,22967,20993,18327,15267,12117,9142,6538,4417,

%U 2807,1667,917,462,210,84,28,7,1

%N The number of times a point sum n is attained in all 7^6 permutations of throwing 7 dice.

%C The sum for any number of dice can be obtained by summing the trailing six terms of the sequence above - assuming leading zeros.

%C 1 1 1 1 1 1

%C 1 2 3 4 5 6 5 4 3 2 1

%C 1 3 6 10 15 21 25 27 27 25 21 15 10 6 3 1

%C 1 4 10 20 35 56 80 104 125 140 125 104 80 56 35 20 10 4 1

%C etc.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Dice">Dice</a>

%F F_{s,i}(k)= sum(n=0, floor((k-i)/s), (-1)^n*binomial(n,i)*binomial(i-1,k-s*n-1)).

%o (PARI) Vec(((sum(k=1,6,x^k))^7+O(x^66))) \\ _Joerg Arndt_, Mar 04 2013

%Y A056150 gives sums for 3 dice.

%Y A108907 gives sums for 6 dice.

%Y A063260 gives the sums for 2 dice through to 6 dice.

%K nonn,fini,full

%O 7,2

%A Robert Goodhand (robert(AT)rgoodhand.fsnet.co.uk), Oct 11 2009