Talk:Square form factorization: Difference between revisions
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Can't say I really followed that, nevermind, a translation of the 2nd C entry fixed my problems. --[[User:Petelomax|Pete Lomax]] ([[User talk:Petelomax|talk]]) 19:23, 20 March 2021 (UTC) |
Can't say I really followed that, nevermind, a translation of the 2nd C entry fixed my problems. --[[User:Petelomax|Pete Lomax]] ([[User talk:Petelomax|talk]]) 19:23, 20 March 2021 (UTC) |
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Just to prove things we working as they should, I wrote a little ditty |
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<lang Phix>integer prev = 3 |
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sequence res = {}, r |
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for n=3 to 100_000 do |
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integer p = get_prime(n) |
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for N=prev+2 to p-2 by 2 do |
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atom f = squfof(N) |
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if f=1 then |
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sequence pf = prime_factors(N) |
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if length(pf)=1 and N=power(pf[1],3) then |
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r = sprintf("%d (%d cubed)",{N,pf[1]}) |
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else |
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r = sprintf("%d (factors: %v)",{N,pf}) |
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end if |
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res = append(res, r) |
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end if |
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end for |
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prev = p |
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end for |
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puts(1,join_by(res,3,10))</lang> |
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and got this, the only things that fail below 1,000,000 are indeed cubes of primes, just as advertised: |
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<pre> |
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24389 (29 cubed) 103823 (47 cubed) 226981 (61 cubed) 389017 (73 cubed) 704969 (89 cubed) 1092727 (103 cubed) |
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68921 (41 cubed) 148877 (53 cubed) 300763 (67 cubed) 493039 (79 cubed) 912673 (97 cubed) 1225043 (107 cubed) |
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79507 (43 cubed) 205379 (59 cubed) 357911 (71 cubed) 571787 (83 cubed) 1030301 (101 cubed) 1295029 (109 cubed) |
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</pre> |
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