2, 3, 6, 7, 14, 15,?

See the below image and you will find a pattern in which numbers are getting added for next number in the given series.
From the given figure , we get the value of sixth term ( ? ) = 69

From the above given series , we have
First term + 350 = Second term
? 156 + 350 = 506
Second term + 550 = third term
? 506 + 550 = ? ? ? = 1056
From the given figure , we get the value of third term ( ? ) = 1056
Third term + 550 = Fourth term
? 1056 + 750 = 1806

The order of above series is given as
First term = 7
Second term = ( First term x 2 ) +9
? Second term = ( 7 x 2 ) + 9 = 14 + 9 = 23
Third term = ( Second term x 2 ) +11
? Third term = ( 23 x 2 ) + 11 = 46 + 11 = 58 is wrong , 57 should be Third term because ( 23 × 2 ) + 11 = 57 .
Similarly we can find all others terms also.
Fourth term = ( Third term x 2 ) +13
? Fourth term = ( 57 x 2 ) +13
Fifth term = ( Fourth term x 2 ) +15
? Fifth term = ( 127 × 2 ) + 15 = 269
Sixth term = ( Fifth term x 2 ) +17
? Sixth term = ( 269 × 2 ) + 17 = 555

As per the details in the question the series is in the form of
First term = 1
Second term = ( First term × Variable ) + Variable
? Second term = ( 1 × 1 ) + 1 = 2
Third term = ( First term × Variable ) + Variable
? Third term = ( 2 × 2 ) + 2 = 8 , So 8 is wrong. we get 6 as Third term.
Similarly , we can find the all terms also.
Fourth term = ( 6 × 3 ) + 3 = 21
Fifth term = ( 21 × 4 ) + 4 = 88
Sixth term = ( 88 × 5 ) + 5 = 445

As per the details in the question the series is in the form of
First term = 2
Second term = ( First term × 3 ) + 1
? Second term = ( 2 × 3 ) + 1 = 7
Third term = ( Second term × 4 ) + 1
? Third term = ( 7 × 4 ) + 1 = 28 is wrong , 29 should be sixth term because ( 7 × 4 ) + 1 = 29 .
So 28 is wrong. we get 29 as Third term.
Fourth term = ( Third term × 5 ) + 1
? Fourth term = ( 29 × 5 ) + 1 = 146
Fifth term = ( Fourth term × 6 ) + 1
? Fifth term = ( 146 × 6 ) + 1 = 877

According to position of alphabets in alphabet table , we have
B C F G ? 2 , 3 ,6 , 7
J K N O ? 10 , 11 , 14 , 15
R S V W ? 18 , 19 , 22 , 23
{ ? Next sequence = Adding 8 in every position of previous sequence alphabets }
Next sequence = 18 + 8 , 19 + 8 , 22 + 8 , 23 + 8
Next sequence = 26, 27, 30, 31 = 26, 27 - 26 = 1, 30 - 26 = 4, 31 - 26 = 5 = Z A D E ( subtract the excess value by 26 )
We get , 26 , 1 , 4 , 5 ? Z A D E = ( ? ) .

From given figure , it is clear that the increasing order of series given as -
First term = 0
Second term = First term + 5
? Second term = 0 + 5 = 5
Third term = Second term + 55
? Third term = 5 + 55 = 60
Similarly , we can find all others terms also.
Fourth term = Third term + 555
? Fourth term = 60 + 555 = 615
Fifth term = Fourth term + 5555
? Fifth term = 615 + 5555 = ?
? Fifth term ( ? ) = 6170

9 7 5 3 1 1/ 8 6 4 2 2/ 9 7 5 3 1/ 8 6 4 2 2 / 9 7 5 3 1/ 8 6 4 2/ 9 7 5 3/ 8 6 4 2

24 ÷ 4 + 6 - 3 x 4 = 6 + 6 - 12 = 0

The pattern of the number series is as given below ;
8 + 2 = 10
10 + 8 (= 2 x 3 + 2) = 18
18 + 26(= 3 x 8 + 2) = 44
44 + 80 (= 3 x 26 + 2) = 124
124 + 424 (= 3 x 80 + 2) = 366