3v4l.org

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<?php $i = 1; for($f = 0; $f <= 20; $f++) { echo "F".$f." = ".abs((($f-1)+$f-2))."\n"; $i++; }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 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 - 8.3.6
F0 = 3 F1 = 1 F2 = 1 F3 = 3 F4 = 5 F5 = 7 F6 = 9 F7 = 11 F8 = 13 F9 = 15 F10 = 17 F11 = 19 F12 = 21 F13 = 23 F14 = 25 F15 = 27 F16 = 29 F17 = 31 F18 = 33 F19 = 35 F20 = 37
preferences:
286.8 ms | 406 KiB | 358 Q