Lah numbers: Difference between revisions
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=={{header|Factor}}==
{{works with|Factor|0.99 development version 2019-07-10}}
<lang factor>USING: combinators combinators.short-circuit formatting infix io
kernel locals math math.factorials math.ranges prettyprint
sequences ;
IN: rosetta-code.lah-numbers
! Yes, Factor can do infix arithmetic with local variables!
! This is a good use case for it.
INFIX:: (lah) ( n k -- m )
( factorial(n) * factorial(n-1) ) /
( factorial(k) * factorial(k-1) ) / factorial(n-k) ;
:: lah ( n k -- m )
{
{ [ k 1 = ] [ n factorial ] }
{ [ k n = ] [ 1 ] }
{ [ k n > ] [ 0 ] }
{ [ k 1 < n 1 < or ] [ 0 ] }
[ n k (lah) ]
} cond ;
"Unsigned Lah numbers: n k lah:" print
"n\\k" write 13 dup [ "%11d" printf ] each-integer nl
<iota> [
dup dup "%-2d " printf [0,b] [
lah "%11d" printf
] with each nl
] each nl
"Maximum value from the 100 _ lah row:" print
100 [0,b] [ 100 swap lah ] map supremum .</lang>
{{out}}
<pre>
Unsigned Lah numbers: n k lah:
n\k 0 1 2 3 4 5 6 7 8 9 10 11 12
0 1
1 0 1
2 0 2 1
3 0 6 6 1
4 0 24 36 12 1
5 0 120 240 120 20 1
6 0 720 1800 1200 300 30 1
7 0 5040 15120 12600 4200 630 42 1
8 0 40320 141120 141120 58800 11760 1176 56 1
9 0 362880 1451520 1693440 846720 211680 28224 2016 72 1
10 0 3628800 16329600 21772800 12700800 3810240 635040 60480 3240 90 1
11 0 39916800 199584000 299376000 199584000 69854400 13970880 1663200 118800 4950 110 1
12 0 479001600 2634508800 4390848000 3293136000 1317254400 307359360 43908480 3920400 217800 7260 132 1
Maximum value from the 100 _ lah row:
44519005448993144810881324947684737529186447692709328597242209638906324913313742508392928375354932241404408343800007105650554669129521241784320000000000000000000000
</pre>
=={{header|Perl 6}}==
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