Catalan numbers/Pascal's triangle: Difference between revisions
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(→{{header|REXX}}: added the REXX language. -- ~~~~) |
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6564120420</pre> |
6564120420</pre> |
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=={{header|Racket}}== |
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<lang Racket> |
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#lang racket |
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(define (next-half-row r) |
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(define r1 (for/list ([x r] [y (cdr r)]) (+ x y))) |
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`(,(* 2 (car r1)) ,@(for/list ([x r1] [y (cdr r1)]) (+ x y)) 1 0)) |
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(let loop ([n 15] [r '(1 0)]) |
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(cons (- (car r) (cadr r)) |
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(if (zero? n) '() (loop (sub1 n) (next-half-row r))))) |
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;; -> '(1 1 2 5 14 42 132 429 1430 4862 16796 58786 208012 742900 |
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;; 2674440 9694845) |
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</lang> |
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=={{header|REXX}}== |
=={{header|REXX}}== |
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<lang rexx>/*REXX program obtains Catalan numbers from Pascal's triangle. */ |
<lang rexx>/*REXX program obtains Catalan numbers from Pascal's triangle. */ |