Frohe Ostern!
# Der Ostersonntag nach Gauss berechnet
sub ostern{
my $X = shift;
my $mon = 3;
my $K = int( $X / 100 );
my $M = 15 + int(( 3*$K+3 ) / 4 ) - int(( 8*$K+13 ) / 25 );
my $S = 2 - int(( 3*$K+3 ) / 4 );
my $A = $X % 19 ;
my $D = (19*$A+$M) % 30 ;
my $R = int( $D / 29 ) + ( int( $D / 28 ) - int( $D / 29 )) * int( $A / 11 );
my $OG = 21 + $D - $R;
my $SZ = 7 - ( $X + int( $X / 4 ) + $S) % 7 ;
my $OE = 7 - ( $OG - $SZ ) % 7;
my $OS = $OG + $OE;
$mon = 4 if $OS > 31;
$OS = $OS - 31 if $OS > 31;
return "$OS.$mon.$X";
}