Pan base non-primes: Difference between revisions
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Thundergnat (talk | contribs) (New draft task and Raku example) |
Thundergnat (talk | contribs) m (minor tweaks) |
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'''"4"''' is ''not'' a prime in every base except bases 2, 3, and 4 where it is an invalid number (and hence not a prime there either.) |
'''"4"''' is ''not'' a prime in every base except bases 2, 3, and 4 where it is an invalid number (and hence not a prime there either.) |
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In general, even pan-base non-primes are much more prevalent than odd, though both are fairly common. |
In general, even pan-base non-primes are much more prevalent than odd, though both are fairly common. |
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With the exception of "10", numeric strings that end in 0 are composite in every base where they are valid. |
With the exception of '''"10"''', numeric strings that end in 0 are composite in every base where they are valid. |
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Numeric strings where the greatest common divisor of all of the digits is more than 1 are composite in every base. |
Numeric strings where the greatest common divisor of all of the digits is more than 1 are composite in every base. |
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put "First 50 pan-base non-primes:\n" ~ @np[^50].batch(10)».fmt("%3s").join: "\n"; |
put "First 50 pan-base non-primes:\n" ~ @np[^50].batch(10)».fmt("%3s").join: "\n"; |
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put "\nFirst 20 odd pan-base non-primes:\n" ~ @np.grep( |
put "\nFirst 20 odd pan-base non-primes:\n" ~ @np.grep(* % 2)[^20].batch(10)».fmt("%3s").join: "\n"; |
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my $threshold = 2500; |
my $threshold = 2500; |
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