It is unclear how you determine num. You can use an array based on power and seed:

$ declare -A num=([10,0]=100 [10,1]=150 [10,2]=200 [10,3]=250 [20,0]=300 [20,1]=350 [20,2]=400 [20,3]=450 [30,0]=133 [30,1]=166 [30,2]=200 [30,3]=233) $ env_parallel -j 50 echo power {1} seed {2} num '${num[{1},{2}]}' ::: 10 20 30 ::: 0 1 2 3 

Or an array based on the sequence number:

$ num=(dummy 100 150 200 250 300 350 400 450 133 166 200 233) $ env_parallel -j 50 echo power {1} seed {2} num '${num[{#}]}' ::: 10 20 30 ::: 0 1 2 3 

It is unclear how you determine num. You can use an array based on power and seed:

$ declare -A num=([10,0]=100 [10,1]=150 [10,2]=200 [10,3]=250 [20,0]=300 [20,1]=350 [20,2]=400 [20,3]=450 [30,0]=133 [30,1]=166 [30,2]=200 [30,3]=233) $ env_parallel -j 50 echo power {1} seed {2} num '${num[{1},{2}]}' ::: 10 20 30 ::: 0 1 2 3 

Or an array based on the sequence number:

$ num=(dummy 100 150 200 250 300 350 400 450 133 166 200 233) $ env_parallel -j 50 echo power {1} seed {2} num '${num[{#}]}' ::: 10 20 30 ::: 0 1 2 3 

Or maybe:

parallel -j 50 echo power {1} seed '{=1 $_=(seq()-1)%4=}' num {2} ::: 10 10 10 10 20 20 20 20 30 30 30 30 :::+ 100 150 200 250 300 350 400 450 133 166 200 233