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<?php $primes = array(); for ($x = 2; $x <= 1000; $x++) { $xIsPrime = TRUE; $sqrtX = sqrt($x); foreach ($primes as $prime) if ($prime > $sqrtX || ((!($x % $prime)) && (!$xIsPrime = FALSE))) break; if ($xIsPrime) echo ($primes[] = $x) . "<br>"; }
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, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 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
2<br>3<br>5<br>7<br>11<br>13<br>17<br>19<br>23<br>29<br>31<br>37<br>41<br>43<br>47<br>53<br>59<br>61<br>67<br>71<br>73<br>79<br>83<br>89<br>97<br>101<br>103<br>107<br>109<br>113<br>127<br>131<br>137<br>139<br>149<br>151<br>157<br>163<br>167<br>173<br>179<br>181<br>191<br>193<br>197<br>199<br>211<br>223<br>227<br>229<br>233<br>239<br>241<br>251<br>257<br>263<br>269<br>271<br>277<br>281<br>283<br>293<br>307<br>311<br>313<br>317<br>331<br>337<br>347<br>349<br>353<br>359<br>367<br>373<br>379<br>383<br>389<br>397<br>401<br>409<br>419<br>421<br>431<br>433<br>439<br>443<br>449<br>457<br>461<br>463<br>467<br>479<br>487<br>491<br>499<br>503<br>509<br>521<br>523<br>541<br>547<br>557<br>563<br>569<br>571<br>577<br>587<br>593<br>599<br>601<br>607<br>613<br>617<br>619<br>631<br>641<br>643<br>647<br>653<br>659<br>661<br>673<br>677<br>683<br>691<br>701<br>709<br>719<br>727<br>733<br>739<br>743<br>751<br>757<br>761<br>769<br>773<br>787<br>797<br>809<br>811<br>821<br>823<br>827<br>829<br>839<br>853<br>857<br>859<br>863<br>877<br>881<br>883<br>887<br>907<br>911<br>919<br>929<br>937<br>941<br>947<br>953<br>967<br>971<br>977<br>983<br>991<br>997<br>

preferences:
275.49 ms | 408 KiB | 326 Q