30 lines
924 B
Lua
30 lines
924 B
Lua
-- Find the first 20 antiprimes.
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-- returns a table of the first goal antiprimes
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function antiprimes(goal)
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local maxNumber = 0
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local ndc = {} -- table of divisor counts - initially empty
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local list, number, mostFactors = {}, 1, 0
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while #list < goal do
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if number > #ndc then
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-- need a bigger table of divisor counts
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maxNumber = maxNumber + 5000
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ndc = {}
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for i = 1, maxNumber do ndc[ i ] = 1 end
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for i = 2, maxNumber do
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for j = i, maxNumber, i do ndc[ j ] = ndc[ j ] + 1 end
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end
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end
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local factors = ndc[ number ]
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if factors > mostFactors then
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table.insert( list, number )
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mostFactors = factors
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end
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number = number + 1
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end
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return list
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end
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-- display the antiprimes
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oo.write( table.concat( antiprimes( 20 ), " " ) )
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