Legendre prime counting function: Difference between revisions
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Phi[x_, 0] := x |
Phi[x_, 0] := x |
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Phi[x_, a_] := Phi[x, a] = Phi[x, a - 1] - Phi[Floor[x/Prime[a]], a - 1] |
Phi[x_, a_] := Phi[x, a] = Phi[x, a - 1] - Phi[Floor[x/Prime[a]], a - 1] |
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pi[n_] := Module[{a}, If[n < 2, |
pi[n_] := Module[{a}, If[n < 2, 0, a = pi[Floor[Sqrt[n]]]; Phi[n, a] + a - 1]] |
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Scan[Print[pi[10^#]] &, Range[0,9]]</lang> |
Scan[Print[pi[10^#]] &, Range[0,9]]</lang> |
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{{out}} |
{{out}} |
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<pre> |
<pre>0 |
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4 |
4 |
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25 |
25 |