"Prime Numbers I"
In math, a prime number is a number only divisible by 1 and itself.
Given the first few prime numbers
2 3 5 7 11 13 17 ...
What is the sum of the first 250 prime numbers? Note that you are seeing the first 7 primes above.
Ok well firstly, make a function to get the next prime, then create a loop up to 250 calculating the next prime, add them together and voila!
Awnser:
2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113 + 127 + 131 + 137 + 139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181 + 191 + 193 + 197 + 199 + 211 + 223 + 227 + 229 + 233 + 239 + 241 + 251 + 257 + 263 + 269 + 271 + 277 + 281 + 283 + 293 + 307 + 311 + 313 + 317 + 331 + 337 + 347 + 349 + 353 + 359 + 367 + 373 + 379 + 383 + 389 + 397 + 401 + 409 + 419 + 421 + 431 + 433 + 439 + 443 + 449 + 457 + 461 + 463 + 467 + 479 + 487 + 491 + 499 + 503 + 509 + 521 + 523 + 541 + 547 + 557 + 563 + 569 + 571 + 577 + 587 + 593 + 599 + 601 + 607 + 613 + 617 + 619 + 631 + 641 + 643 + 647 + 653 + 659 + 661 + 673 + 677 + 683 + 691 + 701 + 709 + 719 + 727 + 733 + 739 + 743 + 751 + 757 + 761 + 769 + 773 + 787 + 797 + 809 + 811 + 821 + 823 + 827 + 829 + 839 + 853 + 857 + 859 + 863 + 877 + 881 + 883 + 887 + 907 + 911 + 919 + 929 + 937 + 941 + 947 + 953 + 967 + 971 + 977 + 983 + 991 + 997 + 1009 + 1013 + 1019 + 1021 + 1031 + 1033 + 1039 + 1049 + 1051 + 1061 + 1063 + 1069 + 1087 + 1091 + 1093 + 1097 + 1103 + 1109 + 1117 + 1123 + 1129 + 1151 + 1153 + 1163 + 1171 + 1181 + 1187 + 1193 + 1201 + 1213 + 1217 + 1223 + 1229 + 1231 + 1237 + 1249 + 1259 + 1277 + 1279 + 1283 + 1289 + 1291 + 1297 + 1301 + 1303 + 1307 + 1319 + 1321 + 1327 + 1361 + 1367 + 1373 + 1381 + 1399 + 1409 + 1423 + 1427 + 1429 + 1433 + 1439 + 1447 + 1451 + 1453 + 1459 + 1471 + 1481 + 1483 + 1487 + 1489 + 1493 + 1499 + 1511 + 1523 + 1531 + 1543 + 1549 + 1553 + 1559 + 1567 + 1571 + 1579 + 1583
= 182109
= 182109
Source:
function check_not_prime($num) { $check = false; for($i = $num - 1; $i > 1; $i--) { if($num % $i == 0) { $check = true; break; } } return $check; } function get_next_prime($num) { do { $num++; } while(check_not_prime($num)); return $num; } function solution(){ $result = 2; $prime = 2;// first prime number echo $prime; for($i = 2; $i <= 250; $i++){ $prime = get_next_prime($prime); $result += $prime; echo " + ".$prime; } echo "<br /><strong>= ".$result."</strong>"; }