Sequence: nth number with exactly n divisors: Difference between revisions
Content added Content deleted
m (→more optimization: added whitespace, added/changed comments, elided a superfluous semicolon.) |
m (→little optimization: optimized the K do loop, increased number of decimal digit precision.) |
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parse arg N . /*obtain optional argument from the CL.*/ |
parse arg N . /*obtain optional argument from the CL.*/ |
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if N=='' | N=="," then N= 15 /*Not specified? Then use the default.*/ |
if N=='' | N=="," then N= 15 /*Not specified? Then use the default.*/ |
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if N>=50 then numeric digits 10 /*use more decimal digits for large N. */ |
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w= 50 /*W: width of the 2nd column of output*/ |
w= 50 /*W: width of the 2nd column of output*/ |
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say '─divisors─' center("the Nth number with exactly N divisors", w, '─') /*title.*/ |
say '─divisors─' center("the Nth number with exactly N divisors", w, '─') /*title.*/ |
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else do; #= 3; y= x%2; end /*Even? " " " " 3.*/ |
else do; #= 3; y= x%2; end /*Even? " " " " 3.*/ |
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/* [↑] start with known num of Pdivs.*/ |
/* [↑] start with known num of Pdivs.*/ |
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do k= |
do k=3 by 1+odd while k<y /*when doing odd numbers, skip evens. */ |
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if x//k==0 then do /*if no remainder, then found a divisor*/ |
if x//k==0 then do /*if no remainder, then found a divisor*/ |
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#=#+2; y=x%k /*bump # Pdivs, calculate limit Y. */ |
#=#+2; y=x%k /*bump # Pdivs, calculate limit Y. */ |
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