I'm looking for this answer, but a better way to do it.
> ({~"1 0 [: i.#) (<@:+:@>)^:(1 |. 2= ] &>) ;/ 1 2 3 2 2 4 2 1
2 2 6 4 2 8 2 1
the right hand side must be boxed. Unboxing at end, just there for display.
Should not assume that it is possible for input.
What the above is doing is if/for a cell that is equal to 2, double the
previous cell.
To get it to work, I've had to generate a full n x n table, and then take the
diagonal. Is there a better tacit way that avoids n x n table?
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