Cubic special primes: Difference between revisions
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(Added Algol W) |
m (→{{header|REXX}}: simplified code, added a foot sep, changed whitespace and comments.) |
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call genP /*build array of semaphores for primes.*/ |
call genP /*build array of semaphores for primes.*/ |
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w= 10 /*width of a number in any column. */ |
w= 10 /*width of a number in any column. */ |
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title= 'the smallest primes < ' commas(hi) " such that the" , |
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'difference of successive terma are the smallest cubic numbers' |
'difference of successive terma are the smallest cubic numbers' |
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if cols>0 then say ' index │'center( |
if cols>0 then say ' index │'center(title, 1 + cols*(w+1) ) /*display the title.*/ |
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if cols>0 then say '───────┼'center("" |
if cols>0 then say '───────┼'center("" , 1 + cols*(w+1), '─') /* " " sep.*/ |
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found= 0; idx= 1 /*initialize number of cbp and index.*/ |
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op= 1 |
op= 1 |
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$= /*a list of |
$= /*a list of cubic primes (so far). */ |
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do j=0 by 0 |
do j=0 by 0 |
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do k=1 until !.np |
do k=1 until !.np |
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np= op + k**3 /*find the next cube plus the oldPrime.*/ |
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if np>= hi then leave j /*Is newPrime too big? Then quit. */ |
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end /*k*/ |
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found= found + 1 /*bump number of primes of this type. */ |
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op= np /*assign the newPrime to the oldPrime*/ |
op= np /*assign the newPrime to the oldPrime*/ |
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if cols |
if cols<0 then iterate /*Build the list (to be shown later)? */ |
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c= commas(np) /*maybe add commas to the number. */ |
c= commas(np) /*maybe add commas to the number. */ |
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$= $ right(c, max(w, length(c) ) ) /*add a |
$= $ right(c, max(w, length(c) ) ) /*add a cubic prime──►list, allow big#.*/ |
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if |
if found//cols\==0 then iterate /*have we populated a line of output? */ |
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say center(idx, 7)'│' substr($, 2); $= /*display what we have so far (cols). */ |
say center(idx, 7)'│' substr($, 2); $= /*display what we have so far (cols). */ |
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idx= idx + cols /*bump the index count for the output*/ |
idx= idx + cols /*bump the index count for the output*/ |
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if $\=='' then say center(idx, 7)"│" substr($, 2) /*possible display residual output.*/ |
if $\=='' then say center(idx, 7)"│" substr($, 2) /*possible display residual output.*/ |
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if cols>0 then say '───────┴'center("" , 1 + cols*(w+1), '─') /*display foot sep. */ |
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say |
say |
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say 'Found ' commas( |
say 'Found ' commas(found) " of " title |
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exit 0 /*stick a fork in it, we're all done. */ |
exit 0 /*stick a fork in it, we're all done. */ |
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/*──────────────────────────────────────────────────────────────────────────────────────*/ |
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
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11 │ 2,531 2,539 3,539 3,547 4,547 5,059 10,891 12,619 13,619 13,627 |
11 │ 2,531 2,539 3,539 3,547 4,547 5,059 10,891 12,619 13,619 13,627 |
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21 │ 13,691 13,907 14,419 |
21 │ 13,691 13,907 14,419 |
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───────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────── |
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Found 23 of the smallest primes < 15,000 such that the difference of successive terma are the smallest cubic numbers |
Found 23 of the smallest primes < 15,000 such that the difference of successive terma are the smallest cubic numbers |
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