Pattern Recognition - 158

Find out the next two numbers in the series.
213 , 7 , 343 , 13 , 773 ,28,1503 , _ , _ ,...............

Answer

213 , 7 , 343 , 13 , 773 ,28,1503 , _ , _ ,...............

213 ,  , 343 ,  , 773 ,   ,1503 , _ , _ ,...............

343  = (21 +13)  3

773  = (34+43)   3

1503= (77+73)   3

Next number

(150+03)   3 = 153 3

213 , 7

7 = (2*3) +1

343 , 13

13 = (3*3) +4

 773 ,28

28 = (7*3) +7

Next number 

(15*3 +0)= 45

213 , 7 , 343 , 13 , 773 ,28,1503 ,45 ,1533 ,...............