Sieve of Eratosthenes

Instructions: Starting from the smallest uncircled number (2 to start), circle the number, and then strike out the multiples of each number from the list below. Then repeat the procedure as long as possible. The circled numbers are the primes.

2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100

Links:

  1. Notice that one is not a prime number! "G. H. Hardy as the last major mathematician to consider 1 to be prime. (He explicitly included it as a prime in the first six editions of "A Course in Pure Mathematics", which were published between 1908 and 1933. He updated the definition in 1938 to make 2 the smallest prime.)"

  2. solution


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