10 lines
215 B
Factor
10 lines
215 B
Factor
USING: kernel math prettyprint sequences ;
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: next ( seq -- newseq )
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[ ] [ last ] [ length ] tri
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[ 2 * 1 - 2 * ] [ 1 + ] bi /
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* suffix ;
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: Catalan ( n -- seq ) V{ 1 } swap 1 - [ next ] times ;
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15 Catalan .
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