Motzkin numbers: Difference between revisions
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This might not be a particularly interesting to describe algorithm (which might be why the task description currently fails to provide any details of the algorithm). Still... it's probably worth an attempt:
This is an inductive sequence on integers with X<sub>0</sub>=1 and X<sub>1</sub>=1 and for the general case of X<sub>n</sub> where n>1, (2+n)X<sub>n</sub> = ((1+2n)X<sub>n-1</sub>+3(n-1)X<sub>n-2</sub>).
So basically we calculate (X<sub>n-1</sub>(1+2n)+3X<sub>n-2</sub>(n-1)) and divide that by 2+n and append this new value to the list. For n we use the list length. For X<sub>n-1</sub> we use the last element of the list. And, for X<sub>n-2</sub> we use the second to last element of the list. For the task we repeat this list operation 40 times, starting with the list 1 1 and check to see which elements of the resulting list are prime. Because these values get large, we need to use arbitrary precision integers for our list values.
=={{header|jq}}==
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