The Easter calculation of Donald Knuth

	function DaynumberToDayAndMonth( daynumber ) {
		// assert( daynumber > 0 && daynumber < 62 );
		if ( daynumber <= 31 ) {
			this.dd = daynumber;
			this.mm = 3;
		} else {
			this.dd = daynumber - 31;
			this.mm = 4;
		}
		return this;
	}
	
	function floor( a ) {
		return Math.floor( a );
	}

	function div( a, b ) { // integer division
		return floor( a / b );
	}

	function DonKnuthGregorianEasterTableLine( year ) {
		var golden_number, century, gregorian_correction, clavian_correction, extra_days, epact;
		// assert( year >= 0 && year <= 4999 );
		golden_number = this.k_gn;
		century = div( year , 100 ) + 1;
		gregorian_correction = div( 3 * century, 4 ) - 12;
		clavian_correction = div( century - 16 - div( century - 18, 25 ), 3 );
		extra_days = ( div( 5 * year, 4 ) - gregorian_correction - 10 ) % 7 ;
		epact = ( 11 * golden_number + 20 + clavian_correction  - gregorian_correction ) % 30;
		if ( epact <= 0 ) {
			epact += 30;
		}
		if ( epact == 25 && golden_number > 11 || epact == 24 ) {
			epact += 1;
		} 
		this.k_ep = epact;
		this.k_ed = extra_days;
		return this;
	}

	function DonKnuthJulianEasterTableLine( year ) {
		var golden_number, extra_days, epact;
		// assert( year >= 0 && year <= 4999 );
		golden_number = this.k_gn;
		extra_days = ( div( 5 * year, 4 ) ) % 7 ;
		epact = ( 11 * golden_number - 4 ) % 30 + 1;
		this.k_ep = epact;
		this.k_ed = extra_days;
		return this;
	}

	function DonKnuthEasterTableLine( year, cal ) {
		var golden_number, day, epact, extra_days, ee;
		// assert( year >= 0 && year <= 4999 );
		golden_number = year % 19 + 1;
		this.k_yr = year;
		this.k_gn = golden_number;
		switch ( cal ) {
			case 'J': // Julian calendar
			    ee = DonKnuthJulianEasterTableLine( year );
				break;
			case 'G': // Gregorian calendar
			    ee = DonKnuthGregorianEasterTableLine( year );
				break;
			case 'A': // Occidental calendar ("Abendländischer Kalender")
			    ee = ( year <= 1582 ) 
				   ? DonKnuthJulianEasterTableLine( year )
				   : DonKnuthGregorianEasterTableLine( year );
				break;
		}
		epact = this.ep;
		extra_days = this.k_ed;
		day = 44 - epact;
		if ( day < 21 ) {
			day += 30;
		}
		this.k_om = day;
		day += 7 - ( day + extra_days ) % 7;
		this.k_os = day;
		return this;
	}

	function DonKnuthEasterTable( annus, times, cal, outputformatter ) {
		// assert( annus >= 0 && annus <= 4996 );
		// assert( times >= 4 && times <= 532 );
		// assert( annus + times <= 5000 );
		for ( let y = annus; y < annus + times; y++ ) {
			var line = DonKnuthEasterTableLine( y, cal );
			outputformatter( line );
		}
	}