Given the series: 4, 7, 12, 21, 38, ......what is the sum of seventh and ninth term?

Answer 1

862

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4= 2*2
7= 2*4- 1
12= 2*7 - 2
21= 2*12 - 3
38= 2*21 - 4
2*38 +5= 81
2*81+ 6= 168 7th term
2*168 +7= 343
343*2 +8 = 694 9th term
Sum of 7th term and 9th term= 168+694= 862