--description--

Consider the following set of dice with nonstandard pips:

$$\begin{array}{} \text{Die A: } & 1 & 4 & 4 & 4 & 4 & 4 \\ \text{Die B: } & 2 & 2 & 2 & 5 & 5 & 5 \\ \text{Die C: } & 3 & 3 & 3 & 3 & 3 & 6 \\ \end{array}$$

A game is played by two players picking a die in turn and rolling it. The player who rolls the highest value wins.

If the first player picks die $A$ and the second player picks die $B$ we get

$P(\text{second player wins}) = \frac{7}{12} > \frac{1}{2}$

If the first player picks die $B$ and the second player picks die $C$ we get

$P(\text{second player wins}) = \frac{7}{12} > \frac{1}{2}$

If the first player picks die $C$ and the second player picks die $A$ we get

$P(\text{second player wins}) = \frac{25}{36} > \frac{1}{2}$

So whatever die the first player picks, the second player can pick another die and have a larger than 50% chance of winning. A set of dice having this property is called a nontransitive set of dice.

We wish to investigate how many sets of nontransitive dice exist. We will assume the following conditions:

• There are three six-sided dice with each side having between 1 and $N$ pips, inclusive.
• Dice with the same set of pips are equal, regardless of which side on the die the pips are located.
• The same pip value may appear on multiple dice; if both players roll the same value neither player wins.
• The sets of dice $\{A, B, C\}$, $\{B, C, A\}$ and $\{C, A, B\}$ are the same set.

For $N = 7$ we find there are 9780 such sets.

How many are there for $N = 30$?

--hints--

nontransitiveSetsOfDice() should return 973059630185670.

assert.strictEqual(nontransitiveSetsOfDice(), 973059630185670);

--seed--

--seed-contents--

function nontransitiveSetsOfDice() {

  return true;
}

nontransitiveSetsOfDice();

--solutions--

// solution required