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You are not logged in. #1 20100119 07:26:17
A silly prime number method.Objective: Find prime numbers below 100, and the First just list the solely 2factors: (2) 4 8 16 32 64 128 The next # is 3, and is prime since it is not above in list. One 3factor and zeroplus 2factors: (3) 6 12 24 48 96 192 Two 3factors and zeroplus 2factors: 9 18 36 72 144 Three 3factors and zeroplus 2factors: 27 54 108 Four 3factors and zeroplus 2factors: 81 162 Next #4 is in list above, not prime, it is 4 = 2 times 2. Next #5 is prime, not listed above. One 5factor and no 3factors and zeroplus 2factors: (5) 10 20 40 80 160 One 5factor and one 3factor and zeroplus 2factors: 15 30 60 120 One 5factor and two 3factors and zeroplus 2factors: 45 90 180 One 5factor and three 3factors and zeroplus 2factors: 135 270 Two 5factors and no 3factors and zeroplus 2factors: 25 50 100 200 Two 5factors and one 3factor and zeroplus 2factors: 75 150 Two 5factors and two 3factors and zeroplus 2factors: 225 450 Three 5factors and and no 3factors and zeroplus 2factors: 125 250 The next # is 6, and is in a list above, so not prime, 6 = 3 times 2. Next the #7 is not listed above so it is prime. One 7factor and no 5factors and no 3factors and zeroplus 2factors: (7) 14 28 56 112 One 7factor and no 5factors and one 3factor and zeroplus 2factors: 21 42 84 168 One 7factor and no 5factors and two 3factors and zeroplus 2factors: 63 126 One 7factor and no 5factors and three 3factors and zeroplus 2factors: 189 378 One 7factor and one 5factor and no 3factors and zeroplus 2factors: 35 70 140 One 7factor and one 5factor and one 3factor and zeroplus 2factors: 105 210 Two 7factors and no 5factors and no 3factors and zeroplus 2factors: 49 98 196 Two 7factors and no 5factors and one 3factor and zeroplus 2factors: 147 294 Next # is 8 and it is in the list of 2factors above, so it is not prime. Then the # 9 is also listed above, so it is not prime, it is 3 times 3. The # 10 is listed above, so it is not prime, it is 5 times 2. Next 11 is prime as it is not listed above. (Now I will abbreviate "factor" with just "f") One 11f and no 7f and no 5f and no 3f and zeroplus 2f: (11) 22 44 88 176 One 11f and no 7f and no 5f and one 3f and zeroplus 2f: 33 66 132 One 11f and no 7f and no 5f and two 3f and zeroplus 2f: 99 198 One 11f and no 7f and no 5f and three 3f and zeroplus 2f: 297 594 One 11f and no 7f and one 5f and no 3f and zeroplus 2f: 55 110 One 11f and no 7f and two 5f and no 3f and zeroplus 2f: 275 550 One 11f and one 7f and no 5f and no 3f and zeroplus 2f: 77 154 One 11f and one 7f and no 5f and one 3f and zeroplus 2f: 231 462 (I am going a bit over 100 here just out of interest and curiosity) One 11f and one 7f and one 5f and no 3f and zeroplus 2f: 385 770 One 11f and one 7f and one 5f and one 3f and zeroplus 2f: 1155 2310 Two 11f and no 7f and no 5f and no 3f and zeroplus 2f: 121 242 Next is 12, which is listed above, so it is not prime, and is 3 times 2 times 2. (I will abbreviate "zeroplus" with "zp" hereafter.) Next # is 13, which is not listed above, so it is a prime number. One 13f and no 11f and no 7f and no 5f and no 3f and zp 2f: (13) 26 52 104 One 13f and no 11f and no 7f and no 5f and one 3f and zp 2f: 39 78 156 (From hereon out I will not type the "no" quantities; wastes space) One 13f and one 5f and zp 2f: 65 130 One 13f and one 7f and zp 2f: 91 182 One 13f and one 11f and zp 2f: 143 286 Next # is 14, which is not a prime number as it is listed above. The #'s 15 and 16 are not prime either as they are listed above. The #17 is prime as it is not listed above. One 17f and zp 2f: (17) 34 68 136 One 17f and one 3f and zp 2f: 51 102 One 17f and one 5f and zp 2f: 85 170 One 17f and one 7f and zp 2f: 119 238 #18 is above listed. The # 19 is prime, not above. One 19f and zp 2f: (19) 38 76 152 One 19f and one 3f and zp 2f: 57 114 One 19f and one 5f and zp 2f: 95 190 One 19f and one 7f and zp 2f: 133 266 Numbers 20, 21, and 22 are found above, so they are not prime. The number 23 is prime and is not listed above. One 23f and zp 2f: (23) 46 92 184 One 23f and one 3f and zp 2f: 69 138 One 23f and one 5f and zp 2f: 115 230 Numbers 24, 25, 26, 27, and 28 are found above, so are factorable and not prime. The number 29 is the next prime and is not listed above. One 29f and zp 2f: (29) 58 116 One 29f and one 3f and zp 2f: 87 174 One 29f and one 5f and zp 2f: 145 290 The number 30 is not prime as it is found under the 5's section above. The number 31 is prime as it is not above. One 31f and zp 2f: (31) 62 124 One 31f and one 3f and zp 2f: 93 186 One 31f and one 5f and zp 2f: 155 310 The numbers 32, 33, 34, 35, and 36 are above so they are not prime. The number 37 is prime as it is not above. One 37f and zp 2f: (37) 74 148 One 37f and 3f and zp 2f: 111 222 The numbers 38, 39, and 40 are found above, so they are not prime. The number 41 is prime since it is not above. One 41f and zp 2f: (41) 82 164 One 41f and 3f and zp 2f: 123 246 The # 42 is found in the 7's section above so it is not prime. The number 43 is not found above, even though 143 is, so 43 is prime. One 43f and zp 2f: (43) 86 172 The #'s 44, 45, and 46 are not prime as they are above. The # 47 is prime as it is not above. One 47f and zp 2f: (47) 94 188 The numbers 48, 49, 50, 51, and 52 are listed above, so they are factorable, or nonprimes. All the factorable nonprime numbers below 100 should be listed above by now, as we are up to fifty, and we have been doubling everything! So if you want to find a prime number between 50 and 100, just search for it above, and if it is not found, it is prime. Let's see if this is true. I'll list the ones not shown above. I wrote all the numbers listed above that were between 50 and 100, inclusive, and then found that 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97 were not listed above, so they are prime numbers. The numbers check with some other internet sources, so that's good. Last edited by John E. Franklin (20100119 10:47:32) igloo myrtilles fourmis #2 20100119 12:43:12
Re: A silly prime number method.I've been reviewing printouts of this, and the data structure "tree's" comes to mind when igloo myrtilles fourmis #3 20100119 19:47:43
Re: A silly prime number method.I take it you have not heard of the sieve of Eratosthenes. #4 20100120 02:32:33
Re: A silly prime number method.Actually, that's where I got the idea!! But with my way, you have to go to halfway, not the square root, so my igloo myrtilles fourmis #5 20100120 05:36:27
Re: A silly prime number method.I guess the point of this exercise was to show you could go through igloo myrtilles fourmis #6 20100120 06:50:44
Re: A silly prime number method.
I alone have the problem of long solutions. When someone comes up with a shorter demonstration than my own, I just scoff.
I like the idea of doing, as I am a poor reader too. I read alot and come away with little. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #7 20100120 07:45:59
Re: A silly prime number method.Thanks for the comments bobby. igloo myrtilles fourmis #8 20100120 08:32:37
Re: A silly prime number method.
As part of a fictitious biography: "In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..." #9 20100120 09:02:09
Re: A silly prime number method.Good one! Or go diagonally, as the work gets harder and easier, in an oscillatory pattern! igloo myrtilles fourmis #10 20100120 12:15:12
Re: A silly prime number method.There was a good scene in "A Beautiful Mind" where JFN efficiently covered an entire blackboard. He even wrote inside the zeros! In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #11 20100121 13:44:33
Re: A silly prime number method.I've worked out the primes up to 500 by skipping products with 2, 3, or 5's in them, and just igloo myrtilles fourmis #13 20100123 07:57:46
Re: A silly prime number method.I'm up to 661 now. Diagonally? I'll keep that in mind. igloo myrtilles fourmis #14 20100129 13:07:23
Re: A silly prime number method.
igloo myrtilles fourmis #15 20100130 04:25:23
Re: A silly prime number method.I have over 12 windows on my screen of columns of numbers now and Last edited by John E. Franklin (20100130 04:36:29) igloo myrtilles fourmis 