Online PHP editor | output for lqjUA

@ 2017-05-18T10:49:46Z

<?php
for ($i = 0; $i < 16; $i++) {
    var_dump(method($i) . "\t" . method1($i) . "\t" . pow(2, $i-1));
}

function method($n) {
    if ($n <= 0) return 0;
    if ($n == 1) return 1;
    if ($n == 2) return 2;
    if ($n == 3) return 4;
    
    return method($n - 1) + method($n - 2) + method($n - 3);
}

function method1($n) {
    if ($n <= 0) return 0;
    
    $r = 1;
    for ($i = 0; $i < $n; $i++) {
        $r += method1($i);
    }
    return $r;
}

Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7: string(7) "0 0 0.5" string(5) "1 1 1" string(5) "2 2 2" string(5) "4 4 4" string(5) "7 8 8" string(8) "13 16 16" string(8) "24 32 32" string(8) "44 64 64" string(10) "81 128 128" string(11) "149 256 256" string(11) "274 512 512" string(13) "504 1024 1024" string(13) "927 2048 2048" string(14) "1705 4096 4096" string(14) "3136 8192 8192" string(16) "5768 16384 16384"

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