For every semiprime N there exists a perfect square Q* that is proximate† to (½*N)2 and for which the greatest common divisor of N and Q is a prime factor of N.
* The value of (½*N)2 is the 2nd adjacent perfect square of N.
† Q is a value that exceeds (½*N)2 by a number of quadratic intervals that is less than ½*sqrt(N).
We can extend this statement to all composites with the caveat that the Q square's GCD will not necessarily be prime.
Sample data includes non-semiprimes (P=prime, S=semiprime, C=all other composites).
|
N |
F1 |
F2 |
Adj2 PS |
Q Squares |
Proximity*
sqrt(Q) / N |
P |
199961 |
199961 |
1 |
9996200361 |
|
|
S |
199963 |
557 |
359 |
9996400324 |
10032225921 |
0.500897666 |
C |
199965 |
13331 |
15 |
9996600289 |
9996800256 |
0.500007501 |
P |
199967 |
199967 |
1 |
9996800256 |
|
|
C |
199969 |
539 |
371 |
9997000225 |
9997600144 |
0.500017503 |
C |
199971 |
1307 |
153 |
9997200196 |
9997400169 |
0.500007501 |
S |
199973 |
643 |
311 |
9997400169 |
10028420164 |
0.500777605 |
C |
199975 |
475 |
421 |
9997600144 |
9998000100 |
0.500012502 |
C |
199977 |
573 |
349 |
9997800121 |
9998000100 |
0.500007501 |
S |
199979 |
15383 |
13 |
9998000100 |
9999200016 |
0.500032503 |
S |
199981 |
6451 |
31 |
9998200081 |
10001200036 |
0.500077507 |
C |
199983 |
623 |
321 |
9998400064 |
9998600049 |
0.500007501 |
C |
199985 |
851 |
235 |
9998600049 |
9999000025 |
0.500012501 |
S |
199987 |
881 |
227 |
9998800036 |
10021411449 |
0.500567537 |
C |
199989 |
823 |
243 |
9999000025 |
9999200016 |
0.500007500 |
S |
199991 |
18181 |
11 |
9999200016 |
10000200001 |
0.500027501 |
S |
199993 |
4651 |
43 |
9999400009 |
10003600324 |
0.500107504 |
C |
199995 |
597 |
335 |
9999600004 |
9999800001 |
0.500007500 |
S |
199997 |
28571 |
7 |
9999800001 |
10000400004 |
0.500017500 |
P |
199999 |
199999 |
1 |
10000000000 |
|
|
C |
200001 |
489 |
409 |
10000200001 |
10000400004 |
0.500007500 |
P |
200003 |
200003 |
1 |
10000400004 |
|
|
C |
200005 |
905 |
221 |
10000600009 |
10001000025 |
0.500012500 |
C |
200007 |
639 |
313 |
10000800016 |
10001000025 |
0.500007500 |
P |
200009 |
200009 |
1 |
10001000025 |
|
|
S |
200011 |
28573 |
7 |
10001200036 |
10001800081 |
0.500017499 |
C |
200013 |
551 |
363 |
10001400049 |
10001600064 |
0.500007500 |
C |
200015 |
545 |
367 |
10001600064 |
10002000100 |
0.500012499 |
P |
200017 |
200017 |
1 |
10001800081 |
|
|
C |
200019 |
1093 |
183 |
10002000100 |
10002200121 |
0.500007499 |
S |
200021 |
1439 |
139 |
10002200121 |
10016006400 |
0.500347464 |
P |
200023 |
200023 |
1 |
10002400144 |
|
|
C |
200025 |
525 |
381 |
10002600169 |
10002800196 |
0.500007499 |
S |
200027 |
631 |
317 |
10002800196 |
10034429584 |
0.500792393 |
P |
200029 |
200029 |
1 |
10003000225 |
|
|
C |
200031 |
669 |
299 |
10003200256 |
10003400289 |
0.500007499 |
P |
200033 |
200033 |
1 |
10003400289 |
|
|
C |
200035 |
3637 |
55 |
10003600324 |
10004000400 |
0.500012498 |
C |
200037 |
509 |
393 |
10003800361 |
10004000400 |
0.500007499 |
C |
200039 |
697 |
287 |
10004000400 |
10004600529 |
0.500017497 |
P |
200041 |
200041 |
1 |
10004200441 |
|
|
C |
200043 |
717 |
279 |
10004400484 |
10004600529 |
0.500007498 |
S |
200045 |
40009 |
5 |
10004600529 |
10005000625 |
0.500012497 |
*Where 0.5 = (½*N)2
The table reveals that some composites are twinned according to Q squares. This means that there are pairs of consecutive odd composites, sometimes separated by primes, whose factors can be derived using the same Q square - even though the factors themselves are different. For example, a single Q shares a GCD1 with C and a GCD2 with C+2 (or C+4), and so on.
Download (702KB) a comma-delimited analysis of all odd Ns from 135691 to 217357
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