This algorithm actually gets exponentially slower as the number increases, so you can't really compare its speed in a 1:1 manner.

2.4.1 :061 > Benchmark.measure { pascalsTriangle(25) }
=> @real=0.000426109

2.4.1 :066 > Benchmark.measure { pascalsTriangle(125) }
=> @real=0.09114601

2.4.1 :062 > Benchmark.measure { pascalsTriangle(250) }
=> @real=3.03741528

2.4.1 :067 > Benchmark.measure { pascalsTriangle(500) }
=> @real=21.5128502

This solution is 30 times slower than mine :) Indeed to understand recursion you have to understand recursion first ;)

Would be nice to define ALPHABET so the submissions don't have to, as well as specify the problem text first, and then it's source info.

Also maybe set a rule/test on ALPHABET needing to be used (to prevent self-defined nato translations).

Y U NO DRY 'Ho'