What number is missing in this sequence? 2; 3; 6; 9; 18; 27; ?; 81

Question

What would be value of ? in the following matrix

6 2 3 5 9  
3 5 6 4 18 
4 9 3 5 27  
2 7 4 5 ? 

Answer 1

54

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2
3
3*2=6
6+3=9
9*2=18
18+9=27
27*2=54
54+27=81

Answer 2

2
3
2x3=6
3x3=9
6x3=18
9x3=27
18x3=54
27x3=81