ganjilgenapprima.php

<?php
# n = (n+1)*(n-1)
# dapatkan nilai ganjil genap dan prima
# jumlah masing masing jika deretnya 100
# ganjil (23): x, y, z
# genap (77): a, b, c
# prima ((7)): g, h, i

for($i=1;$i<=100;$i++){
	$angka = ($i+1)*($i-1);
	echo $angka;
	echo ',';
	if($angka%2==1){
		$ganjil[] = $angka;
	}
	if($angka%2==0){
		$genap[] = $angka;
	}
	$p=0;
	for($j=1;$j<=$angka;$j++){
		if($angka%$j==0){
			$p++;
		}
	}
	if($p==2){
		$prima[] = $angka;
	}
}
echo PHP_EOL;
echo 'ganjil ('.count($ganjil).'): ';
// print_r($ganjil);
while(list($key, $val)= each($ganjil)) echo $val.',';
echo PHP_EOL;
echo 'genap ('.count($genap).'): ';
// print_r($genap);
while(list($key, $val)= each($genap)) echo $val.',';
echo PHP_EOL;
echo 'prima ('.count($prima).'): ';
// print_r($prima);
while(list($key, $val)= each($prima)) echo $val.',';
echo PHP_EOL;