2016 Update

Task/Catalan-numbers/PowerShell/catalan-numbers-1.psh

@@ -0,0 +1,10 @@
+function Catalan([uint64]$m) {
+    function fact([bigint]$n) {
+        if($n -lt 2) {[bigint]::one}
+        else{2..$n | foreach -Begin {$prod = [bigint]::one} -Process {$prod = [bigint]::Multiply($prod,$_)} -End {$prod}}
+    }
+    $fact = fact $m
+    $fact1 = [bigint]::Multiply($m+1,$fact)
+    [bigint]::divide((fact (2*$m)), [bigint]::Multiply($fact,$fact1))
+}
+0..15 | foreach {"catalan($_): $(catalan $_)"}

Task/Catalan-numbers/PowerShell/catalan-numbers-2.psh

@@ -0,0 +1,51 @@
+function Get-CatalanNumber
+{
+    [CmdletBinding()]
+    [OutputType([PSCustomObject])]
+    Param
+    (
+        [Parameter(Mandatory=$true,
+                   ValueFromPipeline=$true,
+                   ValueFromPipelineByPropertyName=$true,
+                   Position=0)]
+        [uint32[]]
+        $InputObject
+    )
+
+    Begin
+    {
+        function Get-Factorial ([int]$Number)
+        {
+            if ($Number -eq 0)
+            {
+                return 1
+            }
+
+            $factorial = 1
+
+            1..$Number | ForEach-Object {$factorial *= $_}
+
+            $factorial
+        }
+
+        function Get-Catalan ([int]$Number)
+        {
+            if ($Number -eq 0)
+            {
+                return 1
+            }
+
+            (Get-Factorial (2 * $Number)) / ((Get-Factorial (1 + $Number)) * (Get-Factorial $Number))
+        }
+    }
+    Process
+    {
+        foreach ($number in $InputObject)
+        {
+            [PSCustomObject]@{
+                Number        = $number
+                CatalanNumber = Get-Catalan $number
+            }
+        }
+    }
+}

Task/Catalan-numbers/PowerShell/catalan-numbers-3.psh

@@ -0,0 +1 @@
+0..14 | Get-CatalanNumber

Task/Catalan-numbers/PowerShell/catalan-numbers-4.psh

@@ -0,0 +1 @@
+(0..14 | Get-CatalanNumber).CatalanNumber