function findFridayThe13ths($startYear, $endYear) {
for ($year = $startYear; $year <= $endYear; $year++) {
for ($month = 1; $month <= 12; $month++) {
$date = strtotime("$year-$month-13");
if (date("N", $date) == 5) { // "N" returns day of the week (1 = Monday, 5 = Friday)
printf("Friday the 13th: %d-%02d-13\n", $year, $month);
}
}
}
}
findFridayThe13ths(2025, 2031);
/*
run:
Friday the 13th: 2025-06-13
Friday the 13th: 2026-02-13
Friday the 13th: 2026-03-13
Friday the 13th: 2026-11-13
Friday the 13th: 2027-08-13
Friday the 13th: 2028-10-13
Friday the 13th: 2029-04-13
Friday the 13th: 2029-07-13
Friday the 13th: 2030-09-13
Friday the 13th: 2030-12-13
Friday the 13th: 2031-06-13
*/
