private long GetSquereFreeBinomilaNumber(int number, int row, Utils.Prime primes)
{
var decomposition = new Dictionary<long, long>();
for (var r = 1; r <= row; r++)
{
var numberDecomposition = primes.GetDecomposition(r);
foreach (var n in numberDecomposition)
{
if (!decomposition.ContainsKey(n.Key))
{
decomposition.Add(n.Key, 0);
}
decomposition[n.Key] += n.Value;
}
}
for (var n = 1; n <= number; n++)
{
var numberDecomposition = primes.GetDecomposition(n);
foreach (var d in numberDecomposition)
{
decomposition[d.Key] -= d.Value;
}
}
for (var n = 1; n <= row - number; n++)
{
var numberDecomposition = primes.GetDecomposition(n);
foreach (var d in numberDecomposition)
{
decomposition[d.Key] -= d.Value;
}
}
if (decomposition.Any(t => t.Value > 1))
{
return 0;
}
return decomposition.Aggregate(1L, (current, d) => current * (long)Math.Pow(d.Key, d.Value));
}