Arithmetic derivative: Difference between revisions
→{{header|J}}: more direct (non-recursive) implementation
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=={{header|J}}==
Implementation:
<lang J>D=: {{ (*y)*+/1*/\.q:1>.|y }}"0</lang>
In other words: find the prime factors of the absolute value of y as a sequence, find and sum each of the products with exactly one value removed from this sequence and multiply by the sign of y. (And since 0 has an infinite list of prime factors which makes treating it nonsensical, use the empty list of prime factors of 1 for that case.)
Task example:
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