Jordan-Pólya numbers: Difference between revisions

=={{header|J}}==

<syntaxhighlight lang=J>P=: p:i.100x

F=: !P

jpfct=: {{ 2}.!x:i.>.!inv 1+y }}

jpprm=: P{.~F I. 1+]

isjp=: {{

if. 2>y do. y

elseif. 0 < #(q:y)-.jpprm y do. 0

else. +./isjp(#~ ] = <.) (%jpfct) y

end.

}}"0

showjp=: {{

if. 2>y do. i.0 return. end.

F=. f{~1 i:~b #inv isjp Y#~b=. (]=<.) Y=. y%f=. jpfct y

F,showjp y%F

}}</syntaxhighlight>

Task:

<syntaxhighlight lang=J> 5 10$I.isjp i.10000

1 2 4 6 8 12 16 24 32 36

48 64 72 96 120 128 144 192 216 240

256 288 384 432 480 512 576 720 768 864

960 1024 1152 1296 1440 1536 1728 1920 2048 2304

2592 2880 3072 3456 3840 4096 4320 4608 5040 5184

<:^:(0=isjp)^:_]1e8

99532800

showjp 99532800

720 720 24 2 2 2</syntaxhighlight>

Note that jp factorizations are not necessarily unique. For example, <tt>120 120 6 6 6 2 2 2 2 2</tt> would also be a jp factorization of <tt>99532800</tt>.