V minor tweak to use seq instead of vector for parent generation, no impact on bench
V minor tweak to use seq instead of vector for parent generation, no impact on bench

Evaluation count : 600 in 60 samples of 10 calls.
             Execution time mean : 112.504997 ms
    Execution time std-deviation : 8.407792 ms
   Execution time lower quantile : 108.038164 ms ( 2.5%)
   Execution time upper quantile : 142.168437 ms (97.5%)
                   Overhead used : 3.376706 ns

Found 6 outliers in 60 samples (10.0000 %)
	low-severe	 1 (1.6667 %)
	low-mild	 5 (8.3333 %)
 Variance from outliers : 55.1694 % Variance is severely inflated by outliers

OliverM/lonelyplanet